Ketubot — Daf 108a

שוקל לו את שקלו ופורע את חובו ומחזיר לו אבידתו ובמקום שנוטלין שכר תפול הנאה להקדש

בשלמא שוקל לו את שקלו מצוה קעביד דתנן תורמין על האבוד ועל הגבוי ועל העתיד לגבות

ומחזיר לו אבידתו נמי מצוה קעביד אלא פורע לו את חובו הא קמשתרשי ליה

אמר רב אושעיא הא מני חנן היא דאמר איבד את מעותיו

ורבא אמר אפי' תימא רבנן הכא במאי עסקינן שלוה על מנת שלא לפרוע

בשלמא רבא לא אמר כרב אושעיא דמוקים לה כרבנן אלא רב אושעיא מ"ט לא אמר כרבא אמר לך רב אושעיא נהי דהנאה לית ליה

the latter may nevertheless pay for him his shekel,  repay his debt  and restore to him any object he may have lost; but where a reward is taken,  the benefit is to be given  to the sacred funds.  Now, one can well be satisfied [with the ruling that] he may 'pay for him his shekel' [because by this payment] he merely performs a religious act,  for it was taught:  It is lawful to withdraw  [from the funds of the Temple treasury] on the account of that which was lost,  collected  or about to be collected;  and [the ruling that he may] restore to him any object he may have lost' [is also intelligible since thereby] also he is performing a religious duty;  but [how could he be permitted to] 'repay his debt' [when thereby] he undoubtedly benefits  him? — R. Oshaia replied: 'This ruling  is that of  Hanan who said: HE LOSES HIS MONEY.  Raba, however, replied: The ruling  may be said [to agree even with the view of] the Rabbis,  for here  we are dealing [with the case of a man] who borrowed money on the condition that he does not repay it [except when he is inclined to do so].  It is well that Raba does not give the same reply as R. Oshaia, since [he wishes] the ruling to agree even with the opinion of the Rabbis. On what ground, however, does not R. Oshaia [wish to] give the same reply as Raba? — R. Oshaia can answer you: Granted that he  has no actual benefit;