Mishnayos Gittin Perek 4 Mishnah 6

In a case of one who sells his slave to gen-tiles, or even to a Jew outside of Eretz Yisrael, the slave is emancipated. Since the slave, who is partially obligated in the fulfillment of mitzvot, would be restricted in his ability to fulfill them in his new situation, either because he would be under the authority of a gentile or because he will no longer be in Eretz Yisrael, the Sages penalized his original owner that he should become a freeman, so that if he succeeds in escaping his new owner, he is a full-fledged freeman. The captives are not redeemed for more than their actual monetary value, for the betterment of the world; and one may not aid the captives in their attempt to escape from their captors for the betterment of the world, so that kidnappers will not be more restrictive with their captives to prevent them from escaping. Rabban Shimon ben Gamliel says: For the betterment of the captives, so that kidnappers will not avenge the escape of the captives by treating other captives with cruelty. And Torah scrolls, phylacteries, or mezuzot are not purchased from the gentiles when they acquire these objects, if they request more than their actual monetary value, for the betterment of the world, so as not to cause an increase in the theft of sacred Jewish ritual objects in order to sell them for large sums of money.

הַמּוֹכֵר עַבְדּוֹ לְגוֹי אוֹ לְחוּצָה לָאָרֶץ, יָצָא בֶן חוֹרִין. אֵין פּוֹדִין אֶת הַשְּׁבוּיִים יוֹתֵר עַל כְּדֵי דְמֵיהֶן, מִפְּנֵי תִקּוּן הָעוֹלָם. וְאֵין מַבְרִיחִין אֶת הַשְּׁבוּיִין, מִפְּנֵי תִקּוּן הָעוֹלָם. רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל אוֹמֵר, מִפְּנֵי תַקָּנַת הַשְּׁבוּיִין. וְאֵין לוֹקְחִים סְפָרִים, תְּפִלִּין וּמְזוּזוֹת מִן הַגּוֹיִם יוֹתֵר עַל כְּדֵי דְמֵיהֶן, מִפְּנֵי תִקּוּן הָעוֹלָם: