Eruvin 100a

עירובין ק׳ ע״א

Learn Eruvin 100a step by step: Aramaic beside English, every question, answer and proof colour-coded.

Open Eruvin 100a in Gemara Clarity

Topic

Using trees and their roots on שבת, and whether someone up a tree may climb down

Overview

The amud opens by finishing an earlier point: carrying under a tree with low branches is limited to בית סאתים, because the space is a דירה שתשמישה לאויר. The גמרא then turns to the משנה's rule that roots three טפחים above the ground may not be sat on. רבה and רב ששת argue about a root that rises above three טפחים and then comes back down near the ground. רבה permits it because anything that low counts as ground, and רב ששת forbids it because it grows from a forbidden source. The גמרא narrows the dispute to roots running sideways and extends it to trees in a ditch, in a corner, and to אביי's palm tree growing through his roof. An attempted proof from the משנה against רבה is rejected, and a ברייתא teaches that on שבת one may not climb, hang from, or lean on a tree or an animal. Two ברייתות disagree about whether someone up a tree may climb down, and the גמרא gives three ways to settle this. רב הונא בריה דרב יהושע then links that disagreement to the argument of רבי אליעזר and רבי יהושע about mixed blood of קרבנות, which turns on whether acting (קום עשה) or not acting (שב ואל תעשה) is better. The גמרא begins to reject that link, and the discussion continues on the next amud.

Opening lines

The steps (29)

1. StatementWhy carrying under the tree is limited to בית סאתים
2. StatementQuoting the משנה about raised roots
3. StatementDispute over roots that come down from above three handbreadths
4. Statementרבה's reason: anything below three handbreadths is ground
5. Statementרב ששת's reason: it comes from a forbidden source
6. ConclusionNarrowing the dispute: upward, downward, and sideways roots
7. StatementThe same dispute applies to a ditch and a corner
8. Statementאביי's palm tree growing through his roof
9. StatementThe permission follows רבה
10. ChallengeIsn't that obvious?
11. ResolutionWe might have thought a house counts as full of earth
12. ChallengeAttempted proof from the משנה that bent-back roots are forbidden
13. RejectionThe משנה teaches about one side being level with the ground
14. ProofA ברייתא confirms the 'one side level' reading and gives the reason
15. StatementNo sitting in a tree all שבת; the same rule for animals; pits and fences are allowed
16. ChallengeTwo teachings contradict each other about climbing down
17. ResolutionIt depends on when he climbed up
18. ResolutionIt depends on whether he climbed by mistake or on purpose
19. ResolutionBoth talk about a mistake, and they argue about penalizing
20. StatementThis argument matches an argument of תנאים about mixed blood
21. StatementThe case of mixed blood and the two opinions
22. Challengeרבי אליעזר: sprinkling once breaks בל תגרע
23. Challengeרבי יהושע: sprinkling four times breaks בל תוסיף
24. Resolutionרבי אליעזר: בל תוסיף applies only to unmixed blood
25. Resolutionרבי יהושע: then בל תגרע also applies only to unmixed blood
26. Proofרבי יהושע: better to break a rule by doing nothing
27. ProofLinking the tree case to the blood-sprinkling debate
28. Rejectionרבי אליעזר may prefer action only when a מצוה is done
29. RejectionSecond rejection: רבי יהושע's view may also be limited