Pesachim page 31b. The Gemara suggests that R Akiva and R. Eliezer disagree about the law of R Isaac. R Akiva holds a lender with a pledge is a paid guard. R Eliezer holds he is an unpaid guard. Tosphot say that means R Akiva is like R Isaac. However, Rashi explains R Isaac to mean the lender with the pledge is a borrower. That means the only way to explain that Gemara is to say that it means that R Akiva and R Eliezer both disagree with R Isaac. Incidentally, I think that one explanation of R Isaac has ot been offered by anyone but it seems to me to be possibly what he meant. Perhaps he means that the lender with eth pledge owns the pledge. So, when the borrower come to pau back the loan, the lender has no obligation to receive the money. If he wants he can keep the pledge since after all, it is his. -------------------------בפסחים דף ל''א ע''ב. The גמרא suggests that ר' עקיבא and ר' אליעזר disagree about the law of ר' יצחק. NOW, ר' עקיבא holds a lender with a pledge is a paid guard. ר' אליעזר holds he is an unpaid guard. תוספות say that meansר' עקיבא is like ר' יצחק. However, רש''י explains ר' יצחק to mean the lender with the pledge is a שואל. That means the only way to explain that גמרא is to say that it means that ר' עקיבא and ר' אליעזר both disagree with ר' יצחק. Incidentally, I think that one explanation of ר' יצחק has not been offered by anyone, but it seems to me to be possibly what he meant. Perhaps he means that the lender with the pledge owns the pledge. So, when the borrower come to PAY back the loan, the lender has no obligation to receive the money. If he wants, he can keep the pledge since after all, it is his.