Eruvin 80b

עירובין פ׳ ע״ב

Learn Eruvin 80b step by step: Aramaic beside English, every question, answer and proof colour-coded.

Open Eruvin 80b in Gemara Clarity

Topic

Fixing a מבוי, keeping a שיתוף מבואות valid, and how much and what food an ערוב needs

Overview

The amud opens by finishing an earlier discussion. The גמרא explains why a source lets residents be forced to fix their מבוי: either that alley had no walls, or a physical fix differs from a side arrangement like an ערוב. Next, רב חייא בר אשי and ריש לקיש argue over whether a לחי or a קורה may be made from אשירה wood. The rule of כתותי מכתת שיעוריה explains why a קורה is harder. A new משנה then teaches how to keep a שיתוף מבואות valid: shrunken food may be topped up quietly, but new residents must be told. It also sets the amount of food (two meals for many residents, a גרוגרת each for few), and רבי יוסי limits that amount to when the ערוב is first made. The גמרא asks what kind of added food the משנה means and resolves it with two answers. It then learns from the משנה that the חכמים disagree with רבי יהודה about including people without their knowledge. Finally, it defines 'many' as eighteen or more people, since two meals equal eighteen figs. A new משנה begins with רבי אליעזר and רבי יהושע arguing over which foods may be used for an ערוב.

Opening lines

The steps (28)

1. ResolutionThat case is different because there are no walls
2. ResolutionAnother version: something done 'from the side' is different
3. StatementDispute: may a לחי or a קורה be made from an אשירה?
4. StatementHow the two opinions relate: wood that must be burned has no size
5. StatementTopping up the food and adding new residents
6. QuestionHow much food is needed?
7. ResponseTwo meals for many people, a dried fig each for few
8. StatementThe amount applies only when first setting up the ערוב
9. StatementCourtyards still make a ערוב so children won't forget
10. QuestionWhat case is the משנה talking about?
11. ChallengeIf the added food is the same kind, why mention only 'shrank'?
12. ChallengeIf the added food is a different kind, informing should be needed
13. ProofA ברייתא: a different kind of food requires informing
14. ResolutionFirst answer: same kind, and 'shrank' means fully crumbled
15. ResolutionSecond answer: different kind, but fully used up is a different case
16. StatementThe משנה's rule shows the Rabbis disagree with רבי יהודה
17. Proofרבי יהודה's own statement about an עירוב made without the person's knowledge
18. ChallengeIsn't the disagreement obvious?
19. ResolutionWe might have limited the משנה to a courtyard between two alleys
20. QuestionHow many residents count as 'many'?
21. Responseשמואל: eighteen people
22. ChallengeOnly exactly eighteen?
23. ResolutionRead it as eighteen and up
24. QuestionWhy exactly the number eighteen?
25. Responseרב יהודה's explanation: when each person gets less than a fig
26. ConclusionA side lesson: two meals equal eighteen figs
27. Statementרבי אליעזר: any food works except water and salt
28. Statementרבי יהושע: only a whole loaf works