Eruvin 78b

עירובין ע״ח ע״ב

Learn Eruvin 78b step by step: Aramaic beside English, every question, answer and proof colour-coded.

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Topic

Ladders, trees, and ditches between two חצרות: when they count as an opening or a divider for עירוב

Overview

רב יוסף asks רבה a series of questions about a ladder that joins two חצרות so they can share one עירוב. If footholds are carved into the wall to widen a narrow ladder, they need to be ten טפחים high. If the whole 'ladder' is carved into the wall, it must reach the top, because bare grooves are hard to climb. רב יוסף then asks about a tree, which may not be climbed on שבת, and an אשירה, which may not be used for any benefit. The גמרא shows that each question could go either way, using the image of a doorway with a lion lying in it. רבה rules that a tree works but an אשירה does not. רב חסדא argues the reverse: only a שבת prohibition should matter for a שבת law. A teaching of רבי אלעזר (some say רבי יוחנן) supports him, while רב נחמן בר יצחק ties both cases to known disputes. A new משנה then teaches that a deep ditch between two חצרות divides them unless it is filled with dirt or pebbles, and that a board four טפחים wide makes a passage across it. The גמרא explains why hay does not fill the ditch. It then begins asking whether dirt fills it without ביטול, and that discussion continues on the next amud.

Opening lines

The steps (23)

1. QuestionHow high must footholds go when they complete a narrow ladder?
2. ResponseTen handbreadths is enough
3. QuestionWhat if the entire ladder is carved into the wall?
4. ResponseThe steps must reach the full height of the wall
5. ChallengeWhy is a fully carved ladder treated differently?
6. ResolutionA real ladder is easy to climb, but bare grooves are not
7. QuestionCan a tree serve as the ladder?
8. QuestionThe question applies according to both רבי and רבנן
9. QuestionWhy the tree question is unclear even according to רבי
10. QuestionWhy the tree might work even according to רבנן
11. QuestionNew question: an אשירה used as a ladder
12. QuestionThe אשירה question applies according to both opinions
13. QuestionWhy רבי יהודה's leniency might not cover an אשירה ladder
14. QuestionMaybe even רבנן would call the אשירה an opening
15. ResponseA regular tree works but an idolatrous tree does not
16. Challengeרב חסדא argues the reverse: the tree should be forbidden and the idolatrous tree permitted
17. ProofA teaching from ארץ ישראל (רבי אלעזר or רבי יוחנן) supports רב חסדא
18. Statementרב נחמן בר יצחק ties both cases to known disputes
19. StatementA ditch between two courtyards, and what fills it
20. StatementA board across the ditch, and balconies facing each other
21. ChallengeChallenge: another משנה treats hay as a real wall
22. ResolutionHay always counts as a wall, but fills a ditch only when left there for good
23. ChallengeDoes dirt fill the ditch even with no stated intent?