Gemara Clarity

Eruvin 4b

עירובין ד׳ ע״ב

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

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Topic

Defending רב's claim that שיעורין, חציצין and מחיצות are הלכה למשה מסיני, then the width needed to lower a too-high מבוי beam

Overview

On the previous amud, רב said that שיעורין, חציצין and מחיצות are a הלכה למשה מסיני. The גמרא challenged this by reading the פסוק 'ארץ חטה ושעורה' as a list of the Torah's measures. This amud finishes that list. תאנה is a גרוגרת for carrying on שבת, רמון is the hole that breaks a vessel, זית is the כזית used for most measures, and דבש is a large date for יום הכיפורים. The גמרא then answers that the measures are really a הלכה למשה מסיני and the verse is only a hint (אסמכתא). Next it challenges חציצין from the פסוק 'ורחץ את כל בשרו'. It concludes that the oral law teaches the details of majority, minority and being מקפיד, following רבי יצחק, and that we do not make a גזירה לגזירה. Then it challenges מחיצות from the ten טפחים of the ארון and כפורת. The answer depends on רבי יהודה and רבי מאיר, and for רבי מאיר the oral law teaches גוד, לבוד and דופן עקומה. Finally the גמרא returns to a מבוי beam higher than twenty אמה, where רב יוסף and אביי disagree about how wide the raised floor must be. That discussion continues on the next amud.

Opening lines

״תְּאֵנָה״: כִּגְרוֹגֶרֶת לְהוֹצָאַת שַׁבָּת.

'Fig': like a dried fig, for carrying out on Shabbat.

״רִמּוֹן״, כְּדִתְנַן:

'Pomegranate': as we learned in a Mishnah:

כׇּל כְּלֵי בַּעֲלֵי בָתִּים

All vessels of homeowners

שִׁיעוּרָן כְּרִימּוֹנִים.

their measure is like pomegranates.

The steps (24)

  1. ProofFig: the measure for carrying on שבת
  2. ProofPomegranate: the size of a hole that makes a vessel broken
  3. ProofOlive: a land whose measures are olive-sized
  4. ChallengeChallenge: not all measures are olive-sized
  5. ResolutionCorrection: most measures are olive-sized
  6. ProofHoney: a large date for יום הכיפורים
  7. ResolutionThe measures are not truly written; the רבנן leaned them on verses
  8. ChallengeInterpositions seem to come straight from the Torah
  9. ResolutionThe oral law is needed for hair, like רבה בר רב הונא's ruling on knots
  10. ChallengeHair is also learned from the Torah
  11. ResolutionThe הלכה teaches the details of majority, minority, and being particular
  12. Statementרבי יצחק's rule: Torah law and two rabbinic decrees
  13. ChallengeWhy not also decree on a minority that he does not mind?
  14. ResolutionWe do not make a decree to protect another decree
  15. ChallengePartitions seem to come from the Torah
  16. ProofProof from the height of the Ark and its cover
  17. ResolutionThe tradition is needed according to רבי יהודה
  18. ChallengeWhat about רבי מאיר, whose cubits make ten?
  19. ResolutionFor רבי מאיר, the tradition teaches other partition rules
  20. QuestionHow much must a too-high beam be lowered?
  21. RejectionThe question is obvious: reduce it as much as needed
  22. QuestionThe real question: how wide must the raised floor be?
  23. Responseרב יוסף says one טפח, אביי says four
  24. StatementA suggested reason: may one use the area under the beam?