Rosh Hashanah 20a

ראש השנה כ׳ ע״א

Learn Rosh Hashanah 20a step by step: Aramaic beside English, every question, answer and proof colour-coded.

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Topic

Whether אדר is always short, adding a day to אלול for practical needs, and when בית דין may delay or hasten ראש חודש.

Overview

The amud opens by finishing a question: is אדר, the month before ניסן, always 29 days? In a second version, רב נחמן tries to prove from the משנה that witnesses may break שבת for ניסן. The גמרא pushes his proof aside. Then רב כהנא shows from the rest of that משנה that breaking שבת needs a real practical reason, and the view that אדר is always short is refuted. Next, עולא reports that אלול was made full so that ראש השנה would not fall next to שבת. The גמרא explains that this was a favor to hot בבל, so that vegetables would not wilt and the dead would not wait two days for burial. A ברייתא seems to forbid adjusting a month for a need. רבא answers that delaying a month is allowed, but sanctifying it early is not, and רבי יהושע בן לוי's rule about pressuring witnesses fits this. רבי יוחנן's teaching seems to contradict it, and אביי and רבא each answer. The amud ends with רב דימי's reversed version and the start of the question about his reason, which is answered on the next amud.

Opening lines

The steps (32)

1. ChallengeIf אדר is always short, why break שבת?
2. ResolutionThere is a מצוה to sanctify based on seeing the moon
3. ProofSecond version: רב נחמן cites the משנה about ניסן and תשרי
4. ProofThe always-short view explains the משנה
5. ProofIf אדר could be full, just add a day
6. RejectionThe משנה means when day 31 falls on שבת
7. Challengeרב כהנא quotes the rest of the משנה about the time of the בית המקדש
8. ProofSo the reason is not the מצוה of sanctifying by sighting
9. ChallengeIf אדר is always short, why break שבת?
10. ConclusionThe challenge stands: a refutation
11. Statementעולא reports that אלול was made full
12. Statementעולא: do the Babylonians know the favor we did them?
13. QuestionWhat is the favor?
14. ResponseTwo reasons: vegetables or the dead
15. QuestionWhat is the difference between them?
16. ResponseFirst answer: יום הכפורים on Sunday
17. ChallengeThe vegetables view should still care about the dead
18. ResolutionNew answer: a יום טוב next to שבת
19. ChallengeThe dead view should still care about the vegetables
20. ResolutionWilted vegetables can be revived in hot water
21. ChallengeWhy only a benefit for בבל?
22. Resolutionבבל is hot, ארץ ישראל is not
23. ChallengeA ברייתא seems to forbid changing the month for a need
24. Resolutionרבא: delaying is different from sanctifying early
25. ResolutionRereading the ברייתא
26. Proofרבי יהושע בן לוי on pressuring witnesses
27. Challengeרבי יוחנן allowed pressuring witnesses to make the month early
28. Resolutionאביי: ניסן and תשרי are different from the other months
29. Resolutionרבא: רבה בר שמואל's ברייתא follows אחרים
30. Proofאחרים: holidays move only four days each year
31. Statementרב דימי teaches the rule about pressuring witnesses in reverse
32. QuestionAsking for the reason behind רב דימי's rule