Reference for Bava Metzia 127:2
א"ל רב אחא בריה דרבא לרב אשי ואי איניש תקיפא הוא דלא יהיב מתנה מאי א"ל דלמא מיגזל גזליה ואבלע ליה בחשבון דתניא הגוזל את חבירו והבליע לו בחשבון יצא
R. Aha the son of Raba asked R. Ashi: But what if he [the lender] is a hard man, who never gives presents? — He replied: He may have robbed him [on a previous occasion], and now included it in the total sum. For it has been taught: If one robbed his neighbour, and then included it in the account, he is quit [of his obligation]. But what if he [the lender] had come from elsewhere, and had never had business dealings with him? — He replied: He [the borrower] might have been robbed by some other person, and might say to him [the lender], 'When so and so borrows money from you, include this in the sum.'