Gittin 44A

ואי בעית אימא: בשלוה על מנת למשכנו, ולא משכנו.

And if you wish, say instead: Even if the time for the slave or the field to be taken as collateral had arrived, there is something novel about this in a case where he borrowed on the condition that the creditors collect from it, i.e., the slave or field, but they did not yet collect from it. Since the field had not yet been collected from the non-Jew by the Jew as payment of the debt, it remains exempt from tithes, but the mere fact that the Jew agreed to have his slave be collected suffices for the rabbinic penalty to take effect, and the slave is emancipated.

תנו רבנן: גבאו בחובו או שלקחו סיקריקון, לא יצא לחירות. ובחובו לא?!

§ A baraita states (Tosefta, Avoda Zara 3:16): If a non-Jew collected a slave for payment of his debt, or the slave was taken by a Sicarius, i.e., one who would use violence and intimidation to force people to give them their property, then he is not emancipated. The Talmud asks: And is it so that if a non-Jew collected a slave for payment of his debt, the rabbis did not institute a penalty and the slave is not emancipated?

ורמינהי: הרי שאנסו בית המלך גורנו, אם בחובו ⁠– חייב לעשר, אם באנפרות ⁠– פטור מלעשר!

And the Talmud raises a contradiction based on what was taught in a baraita: With regard to a case where the household of the king seized one’s threshing floor by force, if they took it for payment of his debt to the king, then he is obligated to tithe in order to render fit for consumption the grain that they seized. The reason for this is because if he were not to tithe it, it would be considered as if he paid a debt using tithe. If they engaged in unjust seizure [anparot] then he is exempt from tithing. This baraita indicates that an item taken for payment of a debt is akin to a sale, so why should the slave taken in payment of the debt not be emancipated?