Gittin 4:6-7

Gittin 4:6

One who sells his servant to a non-Jew or outside of Israel is penalized by having to redeem and free him. For societal benefit, captives must not be ransomed for more than their value (to keep captors from being even more motivated to take people hostage) and they must not be helped to escape (because the captors will take it out on future captives). Rabban Shimon ben Gamliel says that we refrain from doing so because they will take it out on other current captives. (The practical difference is that if there are no other current hostages, Rabban Shimon ben Gamliel would permit facilitating an escape.) Torah scrolls, tefillin and mezuzos may not be purchased from non-Jews for more than their value for the public good (to remove the incentive to steal these things).

Gittin 4:7

If one divorces his wife because she earned a bad (i.e., promiscuous) reputation or because of a vow, he may not re-marry her. Rabbi Yehuda says he may not re-marry her if the vow was widely known but he may if the vow was not widely known. Rabbi Meir says he may not re-marry her if the vow requires a Torah authority to annul but he may if the vow does not require a Torah authority to annul. Rabbi Elazar said that the Sages only prohibited vows that require a Torah authority to annul as a preventive measure because of those vows that don’t require a Torah authority to annul. Rabbi Yosi bar Yehuda says that it occurred in Sidon that a man took a vow saying to his wife, “Konam if I do not divorce you.” He divorced her but the Sages permitted them to remarry because of societal benefit.