Daf 81 (Shabbas 18a-18b)
Summary. The gemara looks at work begun before Shabbas that sets a process in motion that continues on its own.
Pouring water into ink, even without mixing them by hand, is, according to Rebbi, the equivalent of kneading. R’Yose disagrees; for him, kneading is not kneading when no one is kneading.
Allowing a water mill to grind on Shabbas violates the idleness of utensils; i.e. the utensil (in this case, the water mill) is performing an action– and making noise, too. This principle is accepted until the gemara realizes that it is only advocated by Beis Shammai, not Beis Hillel.
The gemara examines rulings by Beis Shammai that appear to contradict the rule on the idleness of utensils. In the case of a brewer’s barrel (in which the barley must be soaked for eight days), if you follow Shammai, a beit din must declare the barrel to be ownerless before the Sabbath.
In some cases, Beis Hillel prohibits leaving articles in an oven or roasting “lest one come to stir the coals on the Sabbath.” A pot of cooked food may be left to simmer.
Hillel and Shammai dispute whether it is permitted to lend or sell to a gentile on a Friday. R’Akiva says, “These acts are permitted even if there is only sufficient time for the gentile to leave the Jew’s house before the Sabbath.”
Comment. What are the goals here?
- No unfinished business should be put in motion before Shabbas unless the originator can put it entirely out of his mind until Shabbas is over.
- All transactions must be above suspicion. Any business with a gentile on the eve of the Sabbath should be curtailed if there is a possibility that an observer might suspect that the Jew is employing the gentile to act as his agent on the Sabbath.