Reference for Ketubot 135:6

רב פפא אמר לא קשיא כאן קודם שיבא לידי גיבוי כאן לאחר שיבא לידי גיבוי:

Papa replied: There is no difficulty: one [refers to a man] before he came under the obligation of repayment, and the other refers to a man after he had come under the obligation of repayment.

Jastrow