Bava Metzia 73B

רב מרי בר רחל משכן ליה ההוא גוי ביתא. הדר זבנה לרבא. נטר תריסר ירחי שתא, שקל אגר ביתא אמטי ליה לרבא. אמר ליה: האי דלא אמטאי למר אגר ביתא עד האידנא, דסתם משכנתא שתא, אי בעי גוי לסלקי לא הוה מצי מסלק לי, השתא לשקול מר אגר ביתא.

The Talmud relates: A certain non-Jew mortgaged a house to Rav Mari bar Raḥel for a loan that Rav Mari had provided him. Afterward, the non-Jew sold the house to Rava. Rav Mari waited for 12 months of the year to pass, took the amount of money necessary to pay rent for the house and brought it to Rava, who was now the owner of the house. Rav Mari said to Rava: This fact that I did not bring the rental fee for the house to the Master until now is because an unspecified mortgage is in effect for a period of one year. If that non-Jew wanted to remove me from the house by paying back the loan, he could not remove me from it until now. Consequently, the house actually belonged to me for that year, and I was not required to pay rent. Now, since the non-Jew can remove me from the house by repaying the loan, the house belongs to you. Therefore, let the Master now take the rental fee for the house for the coming year.

אמר ליה: אי הוה ידענא דהוה ממושכן ליה למר, לא הוה זביננא ליה. השתא כדיניהם עבידנא לך, כל אימת דלא מסלקי בזוזי לא שקיל אגר ביתא. אנא נמי לא שקילנא מינך אגר ביתא עד דמסלקנא לך בזוזי.

Rava said to him: Had I known that this house was mortgaged to the Master, I would not have purchased it at all, as I would have given you the chance to purchase it first. Now, therefore, I will act toward you according to the law of the non-Jews, as I assumed the rights previously held by the non-Jew. According to non-Jew law, as long as the borrower does not remove the lender by paying back the money, he also does not take a rental fee for the house, as there is no prohibition against a non-Jew paying or receiving interest. Therefore, I too will not take a rental fee for the house from you until I remove you by forcing the non-Jew to pay the money that is owed to you.