1) REBBI'S OPINION THAT ONE MUST BE "MEVARER" HIS CLAIM
OPINIONS: The Gemara records a dispute between Rebbi and Raban Shimon ben Gamliel with regard to whether or not a person who claims that he paid back a loan in front of specific witnesses must bring the witnesses to Beis Din to testify and support his claim. Rebbi Shimon ben Gamliel rules that he does not have to bring the witnesses to Beis Din, since his claim that he paid back suffices. Rebbi rules that he must summon the witnesses to Beis Din to support his claim. The Gemara concludes that Rebbi himself agrees that he normally does not need to bring the witnesses to Beis Din to prove that he paid back a loan, but in this case he must bring witnesses to be "Mevarer" ("clarify"). What exactly does this mean?
(a) The RASHBAM (DH Amar Lei) explains that according to Rebbi, since the borrower explicitly mentioned the names of those who saw him pay back the loan, he must show that his claim is true. If he cannot bring those witnesses, it is considered as though he did not pay back the loan.
(b) TOSFOS (DH Ela) quotes RABEINU TAM who questions the Rashbam's explanation. If, in a normal case, merely saying that he paid back suffices to exempt the borrower and he does not have to bring witnesses to Beis Din, then why is he penalized when he mentions the names of the witnesses who saw him pay back? Why does he lose the case if he fails to bring those witnesses to Beis Din?
Rabeinu Tam explains instead that when Rebbi says that the borrower must be "Mevarer," he means that the borrower should clarify his claim if he can. Accordingly, if he brings the witnesses to Beis Din and they say that they never say him repay the loan, then he still owes the money. However, if he cannot find the witnesses, or if they say that they do not remember, he does not owe the money. Later, Rabeinu Tam suggests that it is even possible that if the witnesses deny that they saw him pay back, he may say that they simply do not remember, and thus their testimony does not work against him.
Rabeinu Tam cites support for his explanation from the Gemara in Shevuos (41b). The Gemara there discusses a case in which a person claimed from his friend the 100 Zuz which he had lent to him. The borrower said, "Did I not pay you back in front of these two people?" The two people were summoned to Beis Din, where they said that they had no recollection of witnessing such a repayment. Rava ruled that this does not mean that they never saw the payment, but that they merely did not pay attention to remember the event. According to the Rashbam, why does Rava say that the borrower does not have to pay the lender?
The RITVA records three answers to Rabeinu Tam's proof against the Rashbam's explanation.
1. The Gemara in Shevuos refers to a borrower who was not sure about the identity of the witnesses who saw him pay back the loan. This is evident from the wording that he used, "Did I not pay you back in front of these two people?" Since he was not certain himself, Beis Din does not hold it against him if the witnesses he mentioned have no recollection of the event. In contrast, in the case of the Gemara here the borrower is certain, and thus he must prove that what he claims indeed is what happened.
The Ritva rejects this answer because the expression, "Did I not pay you back...," is also used by the Gemara as an expression of a person who is indignant that his friend does not remember something.
2. The BA'AL HA'ME'OR answers that the Gemara in Shevuos refers to a person who did not specifically ask the witnesses to witness the event, but he merely assumed that they did because they were present. If they say that they did not notice what happened, the borrower cannot be held accountable. In contrast, the Gemara here refers to a person who says that he specifically designated two people to witness the event.
The Ritva has a slight difficultly with this answer, because the Gemara here and in Shevuos make no mention of these specific details of the cases.
3. The RA'AVAD answers that when Rava in Shevuos says that the witnesses merely did not pay attention, he does not mean that the borrower is exempt from paying back. Rather, his intent is to counter the severe statement of Rav Sheshes, who says that the borrower is considered a liar from now on. Rava says that he is not considered a liar, but he agrees that the borrower must pay. (Y. MONTROSE)

170b----------------------------------------170b

2) THE HALACHAH FOLLOWS RAV AND NOT THE TANA'IM OF THE MISHNAH
QUESTION: The Mishnah discusses the proper course of action to take when a borrower repays part of the debt he owes. According to Rebbi Yehudah, the original Shtar should be torn up and the witnesses should sign a new Shtar with the new amount owed, dated from the day of the original loan. According to Rebbi Yosi, the lender keeps the original Shtar and he writes a receipt in which he states that he received a certain amount of money from the borrower towards the repayment of the loan.
In the Gemara, Rav states that the Halachah follows neither of the opinions in the Mishnah. He says that although Rebbi Yehudah's opinion generally would be the proper course of action, such a procedure may be done only by Beis Din and not by the borrower and lender themselves.
The RASHBAM (DH v'Chosvin) addresses the obvious question that Rav, who is an Amora, should not have the authority to argue with the Tana'im. He answers that Rav has the status of a Tana and therefore may argue with the Tana'im. The SHULCHAN ARUCH (CM 54:1) rules like Rav.
The KOVETZ SHI'URIM has difficulty with this ruling. TOSFOS in Kesuvos (8a, DH Rav) writes that it is evident that Rebbi Yochanan did not maintain that Rav had the status of a Tana, as Rebbi Yochanan often argued with Rav. Accordingly, a dilemma arises. There is a rule that when Rav and Rebbi Yochanan disagree, the Halachah follows the view of Rebbi Yochanan (see Beitzah 4a). If the Halachah follows Rebbi Yochanan, then Rav certainly should not have the status of a Tana, since Rebbi Yochanan himself maintained that Rav was not a Tana. Why, then, does the Halachah follow the view of Rav when he argues with Tana'im?
ANSWER: The KOVETZ SHI'URIM posed this question to RABEINU CHAIM HA'LEVI SOLOVEITCHIK who answered that it is inaccurate to say that an Amora cannot argue with a Tana. The general rule is that an Amora presumably would not argue with a Tana if he knew that the Tana said otherwise. This is because every Amora assumed that the Tana'im had a far greater understanding of the topic than he. This is the intent of the Gemara whenever it questions an Amora from the statement of a Tana. However, if an Amora recognizes that his opinion is in disagreement with a Tana and yet he chooses to argue with that Tana anyway, it is possible that the Halachah will follow that Amora. Therefore, Rabeinu Chaim explained, the fact that the Halachah follows the view of Rav does not depend on whether or not Rav had the status of a Tana.
The Kovetz Shi'urim finds support for this explanation in the words of the IGERES D'RAV SHERIRA GA'ON, who notes that there are times that an Amora decides that the text in the Mishnah is not correct and emends it. This shows that an Amora has the ability to argue with a Tanaic statement.
(However, the Kovetz Shi'urim notes that Rav Sherira seems to disagree with Tosfos' conclusion in Kesuvos that Rebbi Yochanan maintained that Rav was not a Tana. See the Kovetz Shi'urim here at length for another opinion with regard to when an Amora may argue with a Tana.) (Y. MONTROSE)

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