Siman - Shabbos Daf 122
- Benefit from melacha done by a gentile
The last Mishnah in the perek states that if a gentile lit a lamp for himself, a Jew may use its light, but if the gentile lit the lamp for the Jew, he may not use it. The same principle applies if a gentile drew water for his animal or built a gangplank to disembark from a boat. The Mishnah concludes with a story of Rabban Gamliel and the zikeinim disembarking on a gangplank that a gentile made.
The Gemara brings a Baraisa that limits the Mishnah’s ruling and states that one can only benefit from the gentile’s work, if שאינו מכירו, the gentile does not know the Jew. Rashi explains that if he knew him, we assume he did the melacha on behalf of the Jew as well.
- Removing and reinserting the door of a carriage, trunk or closet
Based on the opening Mishnah of the seventeenth perek which discusses moving keilim and their doors on Shabbos, the Gemara brings a Baraisa that states that doors of a carriage, trunk or closet may be removed from its socket on Shabbos, but may not be reinserted.
The Gemara asks on the Baraisa, that if the Tanna holds יש בנין בכלים יש סתירה בכלים, that there is a prohibition to build keilim on Shabbos, he must hold that there is a prohibition of demolishing them. And if he holds, אין סתירה בכלים אין בנין בכלים, that there is no prohibition of demolishing keilim, he must hold that there is no prohibition of building them either? So how can removing the doors from their socket be permitted, while reinserting them into their socket be prohibited?
-Abaye answers that the Tanna holds יש בנין בכלים ויש סתירה בכלים, and the Mishnah means to say שניטלו, that they were removed, not that one is permitted to remove them. The Mishnah means that in a situation where the doors were removed, one is prohibited from reinserting them.
-Rava answers that the Tanna holds אין בנין בכלים ואין סתירה בכלים, and the Tanna prohibits reinserting them out of concern that he might wedge them in and then be liable for מכה בפטיש.
- כלי שמלאכתו לאיסור לצורך גופו
The Mishnah stated that one is permitted to take a hammer to crack open nuts on Shabbos.
•Rav Yehudah says that the Mishnah is referring to a hammer that has been designated to crack open nuts but a blacksmith’s hammer would be prohibited. He holds, כלי שמלאכתו לאיסור אפילו לצורך גופו אסור – something that is usually used for work that is forbidden on Shabbos, may not be moved even for a permitted use.
•Rabbah says that the Mishnah is referring to a blacksmith’s hammer. Rabbah holds that כלי שמלאכת לאיסור לצורך גופו מותר – something that is usually used for work that is forbidden on Shabbos, may be used for a permissible purpose.
