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Eruvin 4a

עירובין ד׳ ע״א

Learn Eruvin 4a step by step: Aramaic beside English, every question, answer and proof colour-coded.

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Topic

The size of the Sages' cubit (אביי vs. רבא), then רב's claim that שיעורין are a הלכה למשה מסיני

Overview

This amud finishes the argument between אביי and רבא about whether every cubit the Sages mention is six handbreadths. A ברייתא says all cubits are six handbreadths but 'not exact', which fits רבא. אביי first rewords the ברייתא, and when that fails he says he follows רבן שמעון בן גמליאל. The גמרא then shows that רבא needs no dispute between תנאים: רבן שמעון בן גמליאל only adds that the כלאים cubit is not measured tightly. His words 'a cubit of six' exclude the altar's יסוד and סובב, and a פסוק in יחזקאל shows those used the small cubit of five. Next, the גמרא quotes רב: שיעורין, חציצין and מחיצין are a הלכה למשה מסיני. It challenges this with רב חנן, who says the פסוק 'ארץ חטה ושעורה' teaches measurements. It then explains the foods one by one: wheat, barley and vine. The answer to the challenge comes on the next amud.

Opening lines

שֶׁלֹּא יְהוּ מְכֻוּוֹנוֹת.

provided that they are not exact.

בִּשְׁלָמָא לְרָבָא —

Granted, according to Rava,

כִּי הֵיכִי דְּלִיהֶוְיָין הַלָּלוּ שׂוֹחֲקוֹת

it means: so that these should be generous

וְהַלָּלוּ עֲצֵבוֹת.

and those should be tight.

The steps (14)

  1. ChallengeThe ברייתא fits רבא but challenges אביי
  2. Resolutionאביי rewords the ברייתא to speak only about כלאים
  3. ChallengeThe end of the ברייתא shows the first part spoke about all cubits
  4. Resolutionאביי follows רבן שמעון בן גמליאל
  5. QuestionDoes רבא also need a dispute between תנאים?
  6. Responseרבן שמעון בן גמליאל only adds that the כלאים cubit should not be measured tightly
  7. ChallengeThen why does he say 'a cubit of six'?
  8. Resolution'Six' excludes the altar's base and ledge
  9. ProofThe verse showing the altar's base and ledge used five-handbreadth cubits
  10. Statementרב: measurements, barriers, and partitions are a tradition from Sinai
  11. ChallengeChallenge: measurements seem to come from a פסוק in the תורה
  12. ProofWheat teaches the time measure for a house with צרעת
  13. ProofBarley teaches the measurement for a bone of a dead person
  14. ProofVine teaches the quarter-log of wine for a נזיר