📋 Shiur Overview
Summary of Shiur — Laws of Sanctifying the New Month, Chapter 7
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Introduction — Postponements in Establishing Rosh Chodesh
Rambam: In the previous chapters, the calculation of the molad was studied. In Chapter 7, the Rambam teaches that Rosh Chodesh is not always established exactly according to the molad — there are rules (dechiyos/postponements) that push off Rosh Chodesh to another day.
Explanation: The calculation of the molad itself is already an “average” (mean calculation), and even after that, there are times when we don’t follow the molad, but rather establish Rosh Chodesh on a different day — a day or two later.
Insights and Explanations:
– From the previous chapters we see that what causes Rosh Chodesh is not the appearance of the moon itself, but rather that the Sages established it. Rosh Chodesh is determined through establishment (keviah), not through astronomical facts alone. Now in Chapter 7 we learn further that because Rosh Chodesh is an establishment, we can also determine when it should be established — with specific rules.
– All postponements are part of the calculation itself — it’s not that we calculate the molad and then discuss each year whether to postpone. The calculation already includes the postponements, and one can calculate Rosh Hashanah from today until the end of all generations. The calculation is just “more complicated” than just the molad — one must also calculate the postponements.
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Law 1 — Lo Adu Rosh (Postponement of Adu)
Rambam: “Rosh Chodesh Tishrei is never established… not on Sunday, not on Wednesday, and not on Friday. Their mnemonic is Adu.”
Explanation: Rosh Chodesh Tishrei (= Rosh Hashanah) is never established on Sunday (1st), Wednesday (4th), or Friday (6th). The mnemonic is “Adu”. If the molad falls on one of these three days, Rosh Chodesh is postponed to the next day.
Insights and Explanations:
– The Rambam does not state the reason why we postpone Adu — he doesn’t give an explanation here for why Rosh Hashanah should not fall on these days. However, he says he will give the explanation later, at the end of the chapter (Law 7).
– The rule of Adu only applies when Rosh Chodesh is established through calculation (keviah), not when witnesses come — because with testimony we cannot control which day it falls on.
– The law speaks only of Rosh Chodesh Tishrei — not of all months. This is not entirely clear from the language, but the end of the law (“so that day should not be Adu”) indicates it refers to Tishrei. Ben Aryeh and Yesod Olam are brought as commentators who learn this way — that the inference is correct that it refers only to Tishrei.
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Law 2 — Molad Zaken (Postponement of Molad Zaken)
Rambam: “Similarly, if the molad occurs at midday or after midday — we establish Rosh Chodesh on the following day.”
Explanation: If the molad comes out at midday (18 hours from the beginning of the night) or later, Rosh Chodesh is established on the next day. If the molad is even one chelek before midday, it can be established on that day (provided it is not Adu).
Insights and Explanations:
– “Molad” here means the calculated molad — not when one can see the moon, not when witnesses come. It has nothing to do with seeing the moon. It is a rule in the calculation itself.
– This is not the same matter as in the time of the Temple when Rosh Chodesh was established in the middle of the day (through testimony). Here we’re speaking of a rule in the calculation: if the calculation shows that the molad is after midday, we postpone.
– Midday = 18 hours from the beginning of the night — the Rambam gives the sign “18” which means 18 hours from the start of night (6 hours night + 12 hours = midday). The entire calculation counts 24 hours from the beginning of the night, not divided into day and night separately. All hours are equal hours (not seasonal hours).
– The postponement of molad zaken is a dispute — there is a dispute whether the postponement of “after midday” exists at all (in other opinions). But the Rambam rules that it does.
– This also refers to Rosh Chodesh Tishrei — according to the inference from the language and the commentators (Ben Aryeh, Yesod Olam).
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Law 3 — Two Postponements in Succession (Postponement of Three Days)
Rambam: “If the molad occurs at midday or after midday, and the following day is one of the days of Adu — it is postponed to the day after that, and Rosh Chodesh will be established on the third day from the molad.”
Explanation: If the molad is at midday or later, and the next day is Adu, we postpone another day — Rosh Chodesh is established on the third day from the molad. This is a combination of both postponements — molad zaken and lo Adu — which can lead to a postponement of two days.
Insights and Explanations:
– Example A: The molad is Saturday (day 7) at 18 hours (midday). Due to molad zaken we must postpone to Sunday (day 1), but Sunday is “1” of Adu, therefore we postpone again to Monday (day 2). Rosh Chodesh is established on the third day from the molad.
– Example B: Molad Tuesday midday — we postpone from Tuesday (molad zaken), Wednesday is “4” of Adu, so Rosh Chodesh becomes Thursday.
– Regarding the 24-hour calculation: “Nine hours at night” means 9 hours after the beginning of night — this is still in the night (before dawn). What the Rambam writes “at night” is only a clarification that it’s still in the nighttime, but the number itself always goes from the beginning of the night.
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Law 4 — Postponement of Gatrad (Simple Year, Molad Tuesday Night)
Rambam: “If the molad of Tishrei that comes out in this calculation is on Tuesday night at nine hours of the night and nine hundred and four chalakim of the tenth hour, its sign is Gatrad, and that year is a simple year — we postpone Rosh Chodesh, we don’t establish it on Tuesday… but rather on Thursday.”
Explanation: In a simple year, if the molad of Tishrei comes out Tuesday night, hour 9 + 204 chalakim (sign: 3-9-204), we postpone Rosh Chodesh from Tuesday to Thursday (two days). We cannot make it Wednesday (4 of Adu), so it becomes Thursday.
Insights and Explanations:
– What is new here? This is a special postponement — not molad zaken (because 9 hours at night is long before midday), and not simply Adu (because Tuesday is not Adu). The innovation is that in a simple year, at this specific time point, we postpone from Tuesday.
– Why specifically this measure? The Rambam shows later that the number is exact — “one chelek less” would not have been postponed. The Rambam emphasizes that his numbers are precise.
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Law 5 — Postponement of Btu Takshat (Simple Year After a Leap Year)
Rambam: “Similarly, if the molad of Tishrei comes out on Monday and three hours of the day, and five hundred and eighty-six chalakim — its sign is 2-15-586 — and it is a simple year after a leap year, we establish it on Monday.”
Explanation: In a simple year that comes after a leap year, if the molad is Monday hour 15 + 589 chalakim, we establish Rosh Chodesh on Monday (we don’t postpone).
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Law 6 — General Rule of All Postponements
Rambam: “Thus the method of establishing Rosh Chodesh Tishrei in this calculation is as follows: Calculate and know the molad on which day it is, and how many hours of the day or night and how many chalakim of the hour. And the day of the molad is the established day always, unless it is on Sunday, or Wednesday, or Friday, or if the molad is at midday or after midday…”
Explanation: The Rambam summarizes all the postponements: (1) Adu, (2) molad zaken, (3) Gatrad in a simple year, (4) Btu Takshat in a simple year after a leap year. Generally, the day of the molad is the day of Rosh Chodesh, except in these cases.
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Law 7 — Reason for the Postponement of Adu and the Principle of All Postponements
Rambam: “And now I will explain the reason why we don’t establish in this calculation on the days of Adu, because this calculation is for the conjunction of the moon and sun in their mean motion and not in their true position, as we know.” He brings a proof: “For the molad will be on Tuesday night and the beginning of the month will be Thursday, many times” — the molad (mean) and the true Rosh Chodesh can be two days apart. He brings another proof: when the molad is Tuesday night and we postpone until Thursday — we will see that the moon is still not visible Thursday night, which proves that the postponement is correct.
Explanation: The Rambam gives a reason for the postponements: the calculation of the molad is based on the mean (average motion) of the moon and sun, not on their true position. Therefore we need postponements to correct the calculation. The postponements are not “anti-reality” but the opposite — they bring our calculation closer to reality.
Insights and Explanations:
A) “Lekibutz Hayare’ach Vehashemesh” — What Does Kibutz Mean?
The Rambam mentions “and the sun” — because molad means when the moon is in conjunction with the sun, i.e., when they are in the same place in the sky. The Rambam uses the word “kibutz” for the true astronomical event, and “molad” for the calculated mean. The true conjunction is when something real happens in the sky — the sun and moon are in the actual position. The mean molad is only a calculation tool.
B) The Principle of All Postponements — The Mean Molad Is Not Precise
The Rambam’s foundation is that the mean molad (29-12-793) is not precise — each month has different numbers, because the moon doesn’t go exactly the same speed every month. We took an average of many months. Therefore we need postponements to bring the mean calculation closer to the true molad.
In principle, one could have made a detailed calculation (true molad), but that would have been too complicated. Therefore we took a simpler calculation (an approximation), and then we “fix” the approximation with the postponements.
C) Basic Logic of Postponements: “Every Other Day”
Essentially, every other time we need to add a day. We therefore made a system: Tuesday we establish, Wednesday we postpone, Thursday we establish, Friday we postpone, Saturday we establish — a “half-week” pattern. This is the essence of Adu.
D) The Rambam’s Approach — Adu Is the Main Principle
The Rambam holds that of all four postponements, Adu is the main principle, and the other three postponements (molad zaken, Gatrad, Btu Takshat) are details/derivatives of it. This is an innovation in understanding the structure of the postponements.
E) The Rambam’s Approach: Postponements Are a Calculation Fix, Not a Halachic Enactment
The Rambam holds that in principle one could have made a detailed calculation that would match reality, but such a calculation would have been too complicated. Therefore we made a simpler calculation (an approximation), and then we fix the approximation with the postponements. Lo Adu Rosh is not a separate halachic enactment with practical reasons (like Yom Kippur on Friday, Hoshana Rabbah on Shabbat, etc.), but rather part of the mathematical method to bring the calculation closer to reality.
F) Why Specifically 1, 4, 6?
If this is only a calculation fix, why were specifically 1, 4, 6 chosen? The Rambam’s approach is that it’s simply “every other day” approximately — a regular pattern, not based on specific halachic reasons. The Mekoros Haziuunim brings that the Yerushalmi has other explanations for why these specific days were chosen, but the Rambam doesn’t learn it that way.
G) [Digression: Comparison with Testimony]
In a certain sense, the calculation is “more authentic” than testimony — because witnesses come only after the molad has already occurred (they only see the result), but the calculation calculates the molad itself.
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The Raavad’s Objection to Law 7
A) The Raavad’s Words
Raavad: “Abraham said, the author is very defensive and boasts of this wisdom, which in his eyes is the ultimate redemption, and I do not reach it, for even my teachers did not reach it, therefore I do not enter to examine his words.”
The Raavad says that the author (Rambam) is proud of his wisdom in astronomy. The Raavad admits that he himself doesn’t know this wisdom, and even his teachers didn’t know it, therefore he cannot check the Rambam’s calculations. This is a remarkable situation: the Raavad gives him a jab for pride, but immediately after admits with humility that he actually doesn’t know it — which weakens his criticism. He cannot confirm or deny the Rambam’s calculation, but he assumes that the Rambam is very good at it.
B) The Raavad’s Question: What Did 2, 3, 5 Sin?
The Raavad asks: if the Rambam’s reasoning is that we must postpone because the “true molad” is not then — why shouldn’t we postpone all days? What did 2, 3, 5 (Behaz) sin that we don’t postpone them? If the reason is that the calculation doesn’t match reality, we should always postpone!
The question is weak, because the Rambam’s intention is that we need to postpone half the time and not the other half — we can’t always postpone, because then we would push off too far. This is compared to the Rambam’s rule in Moreh Nevuchim (accepted tradition): one cannot ask “why seven lambs and not eight?” — because there must be some number, and for any number one would ask the same thing. So too here: there must be some days that we postpone, and for any selection one would ask “what did” the others “sin.”
C) The Raavad’s Own Approach: Lo Adu Rosh Has Halachic Reasons
The Raavad brings that Lo Adu Rosh has practical halachic reasons, based on a Yerushalmi (Sukkah): “Pay attention that you should not make the shofar blowing on Shabbat” — Rosh Hashanah should not come out on Shabbat (because of shofar), “and not the willow on Shabbat” — Hoshana Rabbah should not come on Shabbat (because of willow).
The calculation is worked through:
– Hoshana Rabbah is 21 days after Rosh Hashanah (21 Tishrei), thus exactly 3 weeks = same day of the week.
– If Rosh Hashanah is Shabbat → Hoshana Rabbah is Friday (not Shabbat — good).
– If Rosh Hashanah is Sunday (1) → Hoshana Rabbah is Shabbat — bad, because willow does not override Shabbat (except in the Temple).
– Therefore: not 1 Rosh — because of Hoshana Rabbah.
Regarding Yom Kippur:
– Yom Kippur is 10 days after Rosh Hashanah.
– If Rosh Hashanah is Wednesday (4) → Yom Kippur is Friday (erev Shabbat) — bad, because we cannot prepare for Shabbat.
– If Rosh Hashanah is Friday (6) → Yom Kippur is Sunday (motzaei Shabbat) — also bad.
– Therefore: not 4, 6 Rosh — because of Yom Kippur.
Regarding shofar on Rosh Hashanah itself, the law is different: shofar essentially overrides Shabbat (at the court, Temple), so that is not the reason for Lo Adu. The reason is willow (Hoshana Rabbah) which does not override Shabbat.
D) The Fundamental Dispute Between Rambam and Raavad
The main dispute: The Rambam holds that Lo Adu Rosh is part of the mathematical calculation — a way to fix the approximation. The Raavad holds that it has a halachic reason — practical laws like willow on Shabbat, Yom Kippur on Friday.
A possible compromise: perhaps both together — first it was decided that we need to exclude days (calculation reason), and then which days to exclude was chosen based on halachic benefits.
E) Question on the Rambam: Lo Adu Rosh in the Time of Sanctification by Testimony
A strong question on the Rambam: we see that Lo Adu Rosh existed also in the time when they sanctified by testimony (when the month was sanctified according to witnesses). If the Rambam says this is only a way to fix the calculation — this doesn’t work, because in the time of testimony they didn’t need any calculation! The Yesod Olam says that the Rambam’s approach is difficult because of this. Also the Levush and others hold this way.
F) [Digression: The Rambam’s Approach That Astronomy Is a “Secret”]
The Rambam held that the wisdom of intercalation was a secret — “sod ha’ibbur.” This fits with the Gemara’s language “For it is your wisdom and understanding in the eyes of the nations” — it was a contested issue with other groups (Karaites, Muslims). The Rambam wanted to prove that the Jewish sages actually had true astronomical knowledge, and therefore he “boasted” of the wisdom — because it was a sanctification of God’s name to show “acknowledge the sages of Israel.”
📝 Full Transcript
Laws of Sanctifying the Month Chapter 7 — Postponements in Setting Rosh Chodesh Tishrei
Introduction — Postponements in Setting Rosh Chodesh
Speaker 1: Now we’re going to learn Laws of Sanctifying the Month Chapter 7. In the previous chapter we learned when one makes Rosh Chodesh according to the calculation that… whatever… when does one make the calculation? For the molad. When one needs to arrive at it. So when is Rosh Chodesh, ostensibly, one has figured out that it’s not simply that one makes Rosh Chodesh according to the molad. There are certain rules.
The Tosafot tell us that not always does one go, even with the calculation, the calculation is already a certain average as one calls it. There is, yes, the calculation itself is a bit of an average, and even after that, even so, one makes the calculation. Yes, what is there? There are times when one doesn’t make it according to it. One doesn’t reckon with the molad, rather one makes it at a different time. One reckons a different time, a day up, a day up. Yes, but there is a different time.
Perhaps a person could have said this way, that in the previous chapter we don’t know what causes Rosh Chodesh, that the moon has begun to appear, rather that we have established it, the sages of that time have established it. Now we lean more toward that Rosh Chodesh is established, because that’s how it was established.
Speaker 2: Yes, I already know. Okay, yes.
Speaker 1: But we want to know when to establish it, that’s what he wants to know. He doesn’t want to say the measurements, that’s not what he wants to say.
So, it’s like this, there is a law to go this way.
Law 1 — Lo Adu Rosh (Postponement of Adu)
Speaker 1: “One never establishes Rosh Chodesh Tishrei.” Rosh Chodesh Tishrei means Rosh Hashanah. “One doesn’t establish it according to this calculation.” That means, when Rosh Chodesh is when witnesses come, one can’t control that so much. But now that we do this through establishing, can one tell us not to do it on Sunday?
Speaker 2: I don’t know why, one can’t do it when witnesses come, but that’s a different discussion.
Speaker 1: No, because he says… establish according to calculation. It means to say what I told you earlier, what I said about making a calculation.
Speaker 2: Yes, because I can learn it in, that’s why I said my bit of learning.
Speaker 1: He now says this, that since we do it according to calculation, so one can tell us… But he doesn’t mean to say that, rather Rosh Chodesh is when we establish it, we can establish it. He says, so let us not establish it on Sunday. “Rosh Chodesh Tishrei should not be established on Sunday, nor on Wednesday, nor on Friday. Their sign is Adu. Lo Adu Rosh,” the Gemara says, yes?
So, what does this mean to say? In total, what I told you when it’s to make, what isn’t always done? Sometimes one goes outside the rule. Yes, what I said is also three, and it also lies in the words.
So, when don’t things lie in the words? So… the words have many of his great reasons.
Speaker 2: No, that’s not a way of learning.
Speaker 1: So… in short, we do it differently. If there comes a molad of Tishrei on one of these three days, one makes tomorrow Rosh Chodesh.
So these are days of the week, right? Days of the week?
Speaker 2: Yes.
Speaker 1: Is there some concept? What is the concept? He doesn’t say why. What does it matter to us? What does it matter to us that Rosh Hashanah should be Sunday or Wednesday or Friday? He doesn’t say.
Speaker 2: Later? He says why? And perhaps he says later?
Speaker 1: At the end he says end of chapter, from the source establish in this calculation. He’s going to say at the end?
Speaker 2: Okay. Yes.
Speaker 1: He’s going to give the explanation. Okay.
So, “How so?” One can push it back a day. If the molad was on Sunday, one makes it on Monday, and with a molad on Wednesday one establishes. And so on. In short, a day later, forget it.
Law 2 — Molad Zaken (Postponement of Molad Zaken)
Speaker 1: The same thing, another law. Law aleph is one, one law is lo adu. The second law is, that when the molad happens after midday, one makes Rosh Chodesh the next day. Your thing. All these laws are postponements, all these things are times when one makes Rosh Chodesh the next day.
What does it mean for example? “How so? Yes, bet. And likewise if the day falls at midday, or after midday,” after means higher than midday, or further than midday, afterward, “one establishes Rosh Chodesh on the following day.”
I mean, didn’t we learn earlier that in the time of the Beit Hamikdash it could have been Rosh Chodesh in the middle of the day, one established it then.
Speaker 2: He’s not talking about that time, now he’s saying a new thing, now he says, when the molad is in the middle of the day, and we establish it afterward, molad means when the calculation of the molad that we learned earlier is, that’s all it means. It has nothing to do with when one can see the moon, it has nothing to do with adu, it has nothing to do with all these things. All these laws that we’re learning now are laws in the calculation.
Speaker 1: So if the molad, simply a rule, if the molad comes out after midday, or at midday, immediately, thank you very much, from midday and onward, one doesn’t make that day Rosh Chodesh. The rule that one never did so, because when the molad is one can’t yet see the moon, but that’s not the topic.
For example, incidentally, first of all it’s simple, if it’s Monday after midday, one makes it Tuesday. If it’s the… ah, that’s all. “And even if by one chelek,” yes? Ah, on the contrary, if it’s before midday, even by one chelek, one makes it that day, on condition that it’s not from the adu.
Discussion: Does the Law of Molad Zaken Apply to All Months or Only to Tishrei?
Speaker 2: Ah, the “and it shall be if it shall be” also goes up means on Rosh Chodesh Tishrei specifically? Only because he ends “and it shall be that that day should not be adu”. I don’t know. So one is still talking here about the topic of… let’s see, let’s see. Are all the laws about Tishrei? It looks that way from the way he ends, “and it shall be that it should not be”. Perhaps he means if it’s Rosh Chodesh Tishrei? I don’t know.
Speaker 1: What does he say? Well, for this kind of thing the translation would be needed. Your translator doesn’t say. The translator doesn’t say. He doesn’t say. What are the words? He doesn’t say such a simple thing.
Speaker 2: Yes, he says that he’s talking as you say.
Speaker 1: Who told him? I don’t know. He doesn’t begin that the learner should think that it’s so, he could be mistaken in this. He thought that we don’t know. The end reveals it so, but the language… yes.
Tov ben Aryeh, and likewise he brings from the language, and likewise wrote Yesod Olam, and likewise wrote Yesod Olam. Okay, actually actually not clear. He brings from commentators who learn so because of your inference actually. In short, we’re not crazy, you’re right. Ostensibly this is also another law. In general, this whole postponement thing, this is from the Rambam, others argue.
The mistake is making a new section. That makes us mistaken. When it’s a new section one would read it. This is actually another section, the Rambam made it. The Rambam did make it. So there is another, another law, okay? Another law, gimmel. The postponement of after midday there is a dispute in general whether it exists.
So, I don’t know actually how the Rambam meant that we would know that it’s talking about Rosh Hashanah, but so he says that it’s talking about Tishrei. Okay, gimmel, yes?
Discussion: The Nature of the Postponements — Are They Part of the Calculation?
Speaker 1: It can sometimes be also. He’s talking here to the blessing and it shall be, in short, the establishers.
Speaker 2: No, what I mean to say is, those who made the calculation of the molad also wrote when one should postpone. But the postponement he’s talking to us. We know when the molad is according to their calculation. Now let’s check the Rambam.
Speaker 1: This is all clear from a calculation. This is all clear from a calculation. Certainly, the calculation… they already took this into account. That means, whoever calculated, checked when… wasn’t it by whoever? The sages who were righteous with the calendar, when they saw that the molad was on such a day, they already established that Rosh Hashanah should be a different day.
Speaker 2: Yes, but that’s not the topic. If you make the calculation, we already said this in the previous earlier, you want to know when Rosh Hashanah will be, when you make the calculation, when you make the calculation you need to add the rules, because otherwise you won’t know when Rosh Hashanah is. This is all given from the start, this is not something that one decides now. Every year whether it’s a leap year and so on. It doesn’t mean to say that the rabbi who makes Rosh Chodesh today, there’s only one who makes the calculation. The calculation can be made from today until the end of all generations according to the calculation. Only the calculation is a bit more complicated than it was earlier today. One also needs to calculate these things. These things are from the side of the calculation, he’s going to have reasons soon. It’s all from the side of the calculation, it’s not from the side of… there is for Rosh Hashanah.
Speaker 1: Yes, there is on the contrary, the postponements are so that the calculation should fit better. It’s all part of the calculation. So he says in section 7. Okay, let’s go back to here.
So, about this there is a great dispute and practical matters, we’re learning first what it says simply.
Law 3 — Two Postponements in a Row (Postponement for Three Days)
Speaker 1: Okay, another law. It can sometimes be that it should be “that the molad is at midday or after midday,” which was said that then one postpones to the following day. He says, “if the following day is from the days of adu, it is postponed to the day after that,” aha, then one pushes it off by a day, another day. “And Rosh Chodesh will be established on the third day from the day of the molad.”
How so? When does this happen? If “the molad was on Shabbat at midday,” and he gives the sign that it was on day 7, and it was 18. Ah, midday? What is 18? The eighteenth hour? I don’t know, I don’t know. What is the sign?
Speaker 2: Ah, 18 hours from the beginning of the night. Okay.
Speaker 1: 18 hours from the beginning of the night, okay, very good.
So one establishes Rosh Chodesh in a year whose molad is like this
Law 3 (Continued) — Postponement of Adu Combined with Postponement of Molad Zaken
Speaker 1: Okay, let’s go back to here. So he’s talking here about the great dispute and practical matters, we’re learning first what it says simply.
Okay, another law. It can sometimes be that it should be “that the molad is at midday or after midday”, which was said that then one postpones to the following day. He says, “if the following day is from the days of adu, it is postponed to the day after that”. Aha, then one pushes it off by a day, another day. “And Rosh Chodesh will be established on the third day from the day of the molad”.
How so? When does this happen? If “the molad was on Shabbat at midday”, and he gives the sign that it was on day 7, and it was 18.
Ah, midday? What is 18? The eighteenth hour? I don’t know. What is the sign? “18 hours from the beginning of the night”. Okay. 18 hours from the beginning of the night, okay, very good.
So one establishes Rosh Chodesh in a year whose molad is like this, so when? One makes it on Monday. Not Sunday, because Sunday would have been adu. One must push it down from Shabbat, because it’s after less than midday. But it bumped into Sunday, which has the law of lo adu rosh, so it’s on Monday.
“And likewise if the molad was on Tuesday at midday or after midday”, it’s also the same thing, that since it shouldn’t be adu, the dalet of adu, “one establishes Rosh Chodesh on Thursday”. The same thing is from 6. Yes. Okay.
Law 4 — Postponement of Gatrad (Simple Year, Molad on Tuesday Night)
Speaker 1: “A molad of Tishrei that comes out in this calculation on Tuesday night at nine hours of the night”, another postponement, okay. There is, “at nine hours of the night”, yes, “on Tuesday night at nine hours of the night and nine hundred and four chalakim from the tenth hour, its sign is gatrad, and that year was a simple year”.
Discussion: What Does “Nine Hours of the Night” Mean?
Speaker 1: But now one is talking still much before midday, so one wouldn’t need to postpone it. Yes, it’s nine hours of the night, it’s early hours. What does this have to do now?
What does it mean? Nine hours of the night means early? Nine hours of the night, let’s see. No, nine hours of the night means when? No, nine hours from midday? Midday? What does one count from midday? What does nine hours of the night mean? From when does one count all these hours? There isn’t nine hours from after the stars come out at night. From when does one count all these hours?
What was stated in chapter kaf? Seasonal hours? No, not seasonal hours. Equal hours, excuse me. What did we learn? From when does one begin to count the hours? It was stated explicitly in chapter… I don’t know where, in the previous chapter? Yes. Did we learn earlier what hours means, true? Yes, in chapter three and simple. What did we learn?
Let’s finish first the law. If that year was simple, one postpones Rosh Chodesh, one doesn’t establish it on Tuesday in this year, as it should have come out, because it’s on Tuesday, rather on Thursday. Wednesday one can’t, one pushes it to Thursday.
Speaker 2: It says better rabbi and it says better rabbi. Nine hours of the night is the end of the night. It’s daytime, there’s no difference. Nine hours is still the night.
Speaker 1: What are you learning?
Speaker 2: No, because earlier he said 19 hours from midday.
Speaker 1: That’s why I said… not from midday. Midday is 19 hours, because one begins to count the day from… 19 hours from the beginning of the night.
Speaker 2: Thank you very much, because the day always begins at the beginning of the night. Midday is 19 hours.
Speaker 1: But why don’t you say midday is six hours from the beginning of the day?
Speaker 2: You can say that too. We divide it into day and night.
Speaker 1: We don’t divide, we say 24 hours, we don’t say 12 like 12 true, that’s how the calculations reckon, simply it should be easier to calculate. That’s how all hours are reckoned here, that’s easier. Not whoever it’s mixed up, you mean by A.M. P.M. It’s not a good way of reckoning calculations. Anywhere that makes good calculations, reckons twenty-four hours in a day.
So, the nine always means at night, there is no nine during the day. What it says at night is from the beginning of the night, but all numbers here go this way.
Continuation of Law 4
Speaker 1: Now, if it’s nineteen hours plus two hundred four chalakim, or more, in a simple year. What does simple year mean? It wasn’t a leap year. Then one makes Rosh Chodesh Wednesday, from Thursday, Thursday.
What’s a new thing? From Tuesday to Thursday. What’s a new rule? Yes, we don’t know. It would have been after midday. After midday we already know that. But now there’s something new, that once, it says Tuesday, instead of looking after midday, one looks from what time, from after a certain time in the morning.
Speaker 2: Ah, you’re saying that one would push to Wednesday, but one can’t before Wednesday, I also always make that. Yes. So I know that it gets pushed there.
Speaker 1: Okay.
Law 5 — Postponement of Betu Takpat (Simple Year After a Leap Year)
Speaker 1: The same thing, that is if the molad of Tishrei. Here he says a whole time molad of Tishrei, that all these molads that one talks about is molad of Tishrei. And likewise if the molad of Tishrei comes out on Monday and three hours of the day, and five hundred and eighty-nine chalakim. Like weeks and squares. The sign was for this bet tet vav takpat later the Rambam is going to explain the principles of what it is.
If the molad of the simple year that we said would be postponed to Thursday, that he said in section 4, that in a simple year on Tuesday night, the gimmel tet reish dalet one pushes off by two days, minus one chelek. He says that what I said is exact, and likewise the same thing on section 5, never has he said minus a chelek, even just a little bit, one establishes it on Monday. You should know that I’m exact with my numbers.
Law 6 — General Rule of All Postponements
Speaker 1: It turns out? Okay, it comes out after all. The way of establishing Rosh Chodesh of Tishrei in this calculation is taken. Calculate and find the molad on which day it is, and how many hours from the days from the night and how many chalakim from the hour. And the day of the molad is the established day forever, unless it should be on Sunday, or on Wednesday, or on Friday, or if the molad should be at midday or after midday, or if the molad ends in chalakim that don’t have sufficient measure, and it’s in a simple year, or that the molad wasn’t at twenty-five and nine, and it’s in a simple year, or on Monday, and it’s in a simple year after a leap year, that if one of these things occurs one doesn’t establish on the day of the molad, rather on the following day or the day after that, according to the days.
Law 7 — Reason for Postponement of Adu and the Principle of All Postponements
Speaker 1: “And now I will explain the reason why one doesn’t establish in this calculation on the days of adu, because this calculation is for the conjunction of the moon and the sun in their mean motion and not in their true position, as we know.”
I learned previously that the entire molad that we learn here is not the real molad. It’s not when the moon is in conjunction with the sun, which is called the true molad. No, the calculation is just taking a calculation, the halacha of making the moon and the sun. The calculation is only approximate, only an average. Average means one has collected, one calculates a whole year or several years, divides it equally, and arrives at this calculation. But in truth, the truth is that every month has different numbers. Not every month in the year does the moon go exactly that long. So therefore, this is not the true calculation.
Discussion: What Does “Conjunction of the Moon and the Sun” Mean?
Speaker 1: But why does the word “and the sun” come in? “The conjunction of the moon and the sun.”
Ah, okay, the moon is with the sun, opposite the sun. “In their mean motion and not in their true position, as we already know,” as we have already said before.
That the entire calculation of the molad, what is the calculation of the molad that we learned? The number, yes? Remember how the number is? We learned that a day is twelve hours, and seven hundred thirty-nine parts, right? Called 29-12-793, yes? That’s what we call, that’s how we always calculate the molad, the beginning of the calculation, the first step in the calculation to calculate the molad. But the entire calculation is not exact, it’s only a mean molad. And we know this.
So what comes out? “Therefore they made days of establishment and days of postponement.” All these postponements help to bring closer the real calculation to the minute calculation to the real calculation. How, I don’t know, but it is so.
The Essence of Lo Adu Rosh — A Half-Week Pattern
Speaker 1: Ah, so basically, one must, every second time one must add a day. So they simply made a half week. On Tuesday we establish, on Wednesday we postpone, on Thursday we establish, on Friday we postpone, on Saturday we establish, and so on. That’s the sum total.
Lo Adu Rosh Is the Main One of All the Postponements
Speaker 1: And the main thing, all four postponements, what is the main one among them? Lo Adu Rosh, all the other details.
What Does “Conjunction” Mean?
Speaker 1: “So that it should come out” means that it should come out on the day of the true conjunction. Yes, so that the molad should come out in the correct conjunction. What he calls conjunction is not molad, but the true molad. The molad is not just in reality, but the true molad. Something truly happened in heaven, something when the sun and the moon are in the right place. Everything is real, not everything is just to the concern whether it’s exact, whether it’s the minute, or a day before, a day after, or whatever.
It’s a real calculation, it’s not just something that we figured out. One made it so that the calculation is easier. So in a way you can say it’s more real than when witnesses come. When witnesses come it’s only after it’s already happened and one already sees it.
Forget about the witnesses. Our matter is not witnesses. Forget about witnesses. Now we’re talking about your calculation.
Why Not Make an Exact Calculation?
Speaker 1: The truth is, seemingly one could have made an exact calculation, but the calculation is perhaps too complicated. So one made something like an approximation, and then one fixes the approximation. One fixes the approximation a bit with the Lo Adu Rosh.
And the Rambam argues that all these rules, all four postponements, is the essence, that this calculation is what you need.
Proof of the Matter
Speaker 1: Proof of the matter, what is the proof? That the molad will be on Tuesday night and the beginning of the month will be Thursday, many times.
Continuation of Halacha 7 – Postponements of Lo Adu Rosh (Continued)
The Rambam’s Proof: The Postponements Bring the Calculation Closer to Reality
Speaker 1:
Because when witnesses come it’s only after it’s already happened and one already sees it. Forget about the witnesses, our matter is not witnesses, forget about witnesses. Now we’re talking about your calculation.
The truth is, seemingly one could have made an exact calculation, but the calculation is perhaps too complicated. So one made something like an approximation, and then one fixes the approximation. One fixes the approximation a bit with the Lo Adu Rosh.
And the Rambam argues that all these rules, all four postponements, is the essence. That this calculation is the way it works, and proof of the matter, what is the proof? That the molad on Tuesday night is postponed to Thursday, many times, one will see the moon on Thursday night.
He says, look, you’ll think that someone will tell you no, when it just pushes around, it’s not relevant. No, go look at the moon, you’ll see that after it’s already been pushed two days, one still needs to wait a day to see the moon. So it makes sense, because a day after the conjunction one can see the moon.
So you see that the postponements are not anti-reality, on the contrary, the postponements are in order to bring closer the… our calculation with reality. Very good. So…
Question: Why Specifically Aleph, Dalet, Vav?
Speaker 2:
But why was it decided specifically on aleph, dalet, vav? These are just random in order to make it work?
Speaker 1:
That’s what the Rambam says today. It’s simply every other day.
Speaker 2:
Ah, it’s not really with the other day.
Speaker 1:
The Mekorot HaTziyunim looks like something the Yerushalmi has some explanations for why we make the Lo Adu Rosh. Very good. But the Rambam learned that it’s simply every other day approximately. It’s on average, more or less.
There are indeed other reasons, the world struggles with them. But the Rambam learned this way, what should I do?
Speaker 2:
Doesn’t it have to do with which day is before Shabbat?
Speaker 1:
The holy Rambam says it has nothing to do with anything.
The Raavad’s Objection: Lo Adu Rosh Has Halachic Reasons
Speaker 1:
Said the Raavad, yes, look, the holy Rambam doesn’t agree. The holy Raavad, learn the Raavad, what is there to learn, an important piece of Raavad to learn?
Said Avraham, I am not the author of this, very careful and proud of this wisdom, which in his eyes he has reached its purpose. And I do not mean that it came, for even my teachers did not reach it, therefore I will enter to know his words as his colleagues.
A great principle, the Raavad says, listen, the Raavad says, the author is terribly proud that he knows wisdom. I unfortunately don’t know. It’s funny, he gives him a compliment, and a minute later he admits. When he admits that he doesn’t know, and not only does he not know, his rabbi also doesn’t know. He truly comes with humility. Is he right about the pride? No. So he says, I can’t even check how well he knows, but he must be very good.
He writes, the other asks, when the Raavad doesn’t object in Kiddush HaChodesh, it doesn’t mean that the Raavad was that it was right. He simply didn’t know how to calculate. Everything else he was checking after him. But he couldn’t that he was wrong.
But one has already had in this matter something written wonderfully and wondrously. Ah, here one has found something that I can indeed call upon. He found a piece that he remembers from the Gemara. Yes?
The Raavad’s Question: What Did Bet, Gimmel, Heh Do Wrong?
Speaker 1:
Why? Well, the molad on bet, gimmel, heh is not postponed, according to the mean way, why shouldn’t it be postponed to the next day to the true molad?
He asks an interesting question. Something he didn’t understand? According to what I understood, such a question is difficult to explain.
The Raavad only gives an explanation. The Raavad says, I only have here like a proof. One must postpone because the true molad is not then. If one should always postpone. That’s the Raavad’s question.
What did bet, gimmel, and heh do wrong? It’s such a funny question, because I understood that we want to make it half the time yes and half the time no. That’s how I understood, but the Raavad understood something differently.
The Raavad’s Answer: Reasons of Hoshana Rabbah and Yom Kippur
Speaker 1:
Then he says and I according to us, another explanation. The postponement from there says Rava so that it shouldn’t come on Shabbat, because I saw a language in the Yerushalmi that they bring.
Ah, according to us, he doesn’t bring understanding understanding. What does such a Yerushalmi mean? In the Mekorot HaTziyun he brought here a Yerushalmi Sukkah, give your attention that you should not leave its blowing on Shabbat, Rosh Hashanah should not come out on Shabbat, and not aravah on Shabbat, the aravah of the holiday should not come on Shabbat.
Speaker 2:
Rosh Hashanah does come out on Shabbat. Blowing? Perhaps he reads the blowing of Yom Kippur?
Speaker 1:
Again. One day of Rosh Hashanah already comes Shabbat, that will always be so, I don’t know. Okay.
He says, the Raavad says that aravah means that Hoshana Rabbah shouldn’t be Shabbat, so one makes it yes.
Discussion: Calculation of Hoshana Rabbah
Speaker 2:
If one will make it there, right? When is Hoshana Rabbah? How many days after Rosh Hashanah?
Speaker 1:
If one will make Friday Rosh Hashanah, what will come Hoshana Rabbah Shabbat? What’s the calculation? Which day of Rosh Hashanah is what? The 29th?
Speaker 2:
Rosh Hashanah is the 1st of Tishrei.
Speaker 1:
No, sorry, I mean to say Hoshana Rabbah. Hoshana Rabbah is when? How many days after? How many weeks after?
Two weeks after Rosh Hashanah, exactly the same day of the week, Sukkot begins. Hoshana Rabbah is a week in, seven days of Sukkot, but one day less, right?
If Rosh Hashanah is Shabbat, Hoshana Rabbah comes out Friday. Right? And if Rosh Hashanah will be Sunday, Hoshana Rabbah will come out Shabbat. And if it comes out Wednesday, it’s already with a different calculation. I also want to help with Yom Kippur. Okay.
Again, if Rosh Hashanah is… so, what is aravah day? What bothers us so much that Hoshana Rabbah is on Shabbat?
Speaker 2:
Because aravah is one that overrides Shabbat.
Speaker 1:
However, and you know with… ah, seemingly it goes like this, because you know in the Temple one did override Hoshana Rabbah on Shabbat. Yes, lulav aravah, if on the day of the announcement it’s not relevant. In the Temple it does override Shabbat. Lulav aravah, the seventh of it is the seventh.
Speaker 2:
Why didn’t they make the halacha that we should be able to blow shofar that Rosh Hashanah shouldn’t come out on Shabbat?
Speaker 1:
I ask, I said a good question. But in any case, the beautiful Rava… ah, because Rosh Hashanah does override Shabbat, in principle, both in the Temple, both in the court, and the like.
Speaker 2:
No, one can blow.
Speaker 1:
Which is the opposite, doesn’t make sense.
Speaker 2:
No, what I’m saying doesn’t make sense. I don’t know what you’re asking, one needs to get confused.
Speaker 1:
In any case, that was the…
Discussion: Calculation of Yom Kippur
Speaker 1:
Rashi: Yom Kippur should not come on Friday or on Saturday night.
And what about Yom Kippur? If Yom Kippur will be… let’s understand the calculation. If Rosh Hashanah will be aleph, who will Yom Kippur be?
Speaker 2:
No, Yom Kippur won’t be Shabbat. That’s for a rabbi.
Speaker 1:
If Yom Kippur will be, Rosh Hashanah will be dalet, Yom Kippur is ten days later, it comes out when? Shabbat, or Friday, huh?
Let’s calculate, if Rosh Hashanah is Wednesday, yes, ten days later will be Friday, erev Shabbat. We don’t want Yom Kippur to be erev Shabbat, because we have no time to prepare Shabbat or what? I don’t know, and conversely, one minute let’s see, and that’s if Rosh Hashanah is Wednesday, and if it’s vav, Yom Kippur comes out erev Shabbat. We don’t want both. And very good.
And that’s the Raavad’s, let’s see what he brings the holy rabbi. He still finishes how it truly comes to him. What is the matter of the Yerushalmi? Yes, what is the matter of the bottom? I don’t know.
In short, the Raavad doesn’t buy it.
The Foundation of the Dispute: Calculation or Halacha?
Speaker 1:
In other words, here lies a fundamental thing. The Rambam holds that Lo Adu Rosh has a different reason. It’s not part of the calculation, but it has a halachic reason. It’s a practical calculation.
The Rambam looked at this as essentially showing that the calculation. The Rambam had no interest in incorporating everything into the calculation.
Speaker 2:
What would the rabbi have wanted that the entire molad should be a decree of Scripture? What would he have wanted to know?
Speaker 1:
What is the Yerushalmi’s aravah deed, what does it mean? What is the meaning of the Yerushalmi’s aravah deed? Let’s be lazy and look at this. No Yerushalmi at all, I don’t know.
Clarification of the Yerushalmi: Aravah Deed
Speaker 1:
Says the holy one, this… can one prepare the aravah for Rosh Hashanah? Let’s see. It says like this, in the Yerushalmi it says, and he brings a Gemara, if Yom Kippur, deeds means if dead people will die on Sunday, one won’t bury them until Monday, because the world will be busy.
If the Hoshana Rabbah is correct, what is the problem? I’m not explaining.
Speaker 2:
What do the colleagues say about what he doesn’t know?
Speaker 1:
Yes, the Maggid struggles with what the Raavad’s question is. Interesting, this piece?
The Maggid Mishneh’s Answer: What Did Bet, Gimmel, Heh Do Wrong
Speaker 1:
He made, I understood the Raavad’s questions, and one had to always postpone. He says, no, why wouldn’t one postpone? He says, well, and when would one do the opposite? You asked then.
He says, just as the Rama says that one should make a sign on the pots of milk. Why shouldn’t one make a sign on the pots of meat? Because then he brought one question.
So he brings from the Maggid Mishneh. That’s like the Rambam who says, one can’t ask why seven sheep, because if it were eight, I would have asked why eight. There must be some number, let there be a number.
Speaker 2:
No, let’s see. What did they do wrong? Understand? It’s like this, what merit did they have?
Speaker 1:
I didn’t like that it’s random. The Rambam held that it’s random, that one should make a half. He held that it must have some clear law.
Well, so it’s good. Can one indeed say that the reasons from the Gemara are why one chose these days, not… that it should have another benefit. It can be both together. That it should have a good benefit. It means, first one made the calculation that one needs to skip days. Which days should one skip, one calculated what is better. Fine.
So what’s the problem? What is this Yerushalmi? Where does it say, what does it bring?
So do you want to check the Yerushalmi? Yes, let’s check the Gemara.
Question on the Rambam: Lo Adu Rosh in the Time of Sanctification by Witnesses
Speaker 1:
Ah, there’s a question, that one sees that Lo Adu Rosh was also when they sanctified by witnesses. Then, according to the Rambam that this is only a way to fix the calculation in the heights of the commandment, it doesn’t make sense.
He brings that the Yesod Olam says it doesn’t help, the Rambam is calculation. Yes, he indeed says so, as I thought, Levush and others.
The Rambam’s Explanation: The Secret of Intercalation
Speaker 1:
Certainly, the claim in the Gemara is very weak, it doesn’t make sense. It must be a secret of intercalation, the claim is living calculation.
The Rambam had the idea that there was some secret, one may not know, this is our molad, this is not true, this is a secret. You don’t want to say it.
Speaker 2:
Yes, Rashi… I guess because then the Muslims were busy with this, what is… I don’t know who, the Karaites, or someone with whom one had a dispute, or the Gemara is a secret of intercalation.
Speaker 1:
One sees the acknowledgment of the sages of Israel, and this, “For it is your wisdom in the eyes of the nations,” it was a contested issue.
Yes, but as if, he says to a Jew, why is today Rosh Hashanah? That means the sages saw the moon. No, you know it’s not true, the whole thing of something, for summer is the met, the astronomy, one kept a secret.
So the Rambam makes it sound.