The Gemara concludes: The refutation of the opinions of all the amora’im who held that a person who became blind after witnessing a matter can, in certain cases, testify about it, is indeed a conclusive refutation.

§ Rabbi Abba sent another ruling to Rav Yosef bar Ḥama: One who says something concerning one child among his sons is deemed credible, and Rabbi Yoḥanan says that he is not deemed credible.

The Gemara asks: What is Rabbi Abba saying? Abaye said that this is what Rabbi Abba is saying: One who says concerning one child among his sons: He shall inherit all my property, is deemed credible, in accordance with the opinion of Rabbi Yoḥanan ben Beroka, who holds that one can bequeath all his property to one of his heirs (130a). And Rabbi Yoḥanan says that he is not deemed credible, in accordance with the opinion of the Rabbis, who disagree with Rabbi Yoḥanan ben Beroka.

Rava objects to this explanation: According to Abaye’s explanation, this wording: Is deemed credible, and: He is not deemed credible, is not precise; he should have employed the terms: Shall inherit, and: Shall not inherit, as the issue is the ability of the father to specify who will inherit from him, not his credibility.

Rather, Rava said that this is what Rabbi Abba is saying: One who says about one child among his sons that he is his firstborn is deemed credible, in accordance with the opinion of Rabbi Yehuda (127b); and Rabbi Yoḥanan says that he is not deemed credible, in accordance with the opinion of the Rabbis, who disagree with Rabbi Yehuda.

§ Rabbi Abba sent another ruling to Rav Yosef bar Ḥama: In a case of one who says: My wife will take a portion of my estate like one of the sons, she takes a portion like one of the sons, as it is considered a gift. Rava says: And this ruling is only with regard to the husband’s current property, which he can give her as a gift. The husband cannot give her a portion of his future property. And furthermore, the calculation of her portion must take into account not only the number of sons the husband has at the time of his statement, but also the sons who come, i.e., who will be born, afterward.

§ Rabbi Abba sent another ruling to Rav Yosef bar Ḥama: In the case of one who produces a promissory note against another, and the creditor says: I was not repaid anything, and the debtor says: I repaid half the debt, and the witnesses testify that the debtor repaid the entire debt, then this debtor takes an oath that he repaid half, as is the halakha with regard to one who admits to a part of a claim, and he is exempt from paying that half. And the creditor collects the second half from unsold property; but not from liened property that was sold after the loan, as the buyers can say: We rely on the witnesses that the debt was repaid in its entirety.

The Gemara compares this halakha to the case of a promissory note that states that the debtor owes the creditor: Sela coins, without stating how many. The creditor claims that he lent the debtor five sela and the debtor claims that he borrowed only three. Rabbi Akiva holds that since the wording of the promissory note indicates a minimum debt of two sela, and the creditor could not have collected the third sela without the debtor’s admission, the latter’s admission to a part of the claim cannot render him liable to take an oath. The Gemara states: And even according to Rabbi Akiva, who says that the debtor is not liable to take an oath, as with regard to the third sela his legal status is similar to that of one who returns a lost item, this statement applies only in a case where there are no witnesses to the loan. But where there are witnesses, as is the case in Rabbi Abba’s ruling, the debtor fears denying the entire debt. Therefore he is liable to take an oath that he repaid half, as one who admits to a part of the claim.

Mar bar Rav Ashi objects to this: On the contrary; even according to Rabbi Shimon ben Elazar, who disagrees with Rabbi Akiva and says that the debtor is considered one who admits to a part of the claim, this statement applies only in a case where there are no witnesses who support him. But here in the case of Rabbi Abba, where there are witnesses who support him, testifying that he repaid the entire debt, his legal status is certainly that of one who returns a lost item, and he does not need to take an oath that he repaid half.

§ Mar Zutra taught in the name of Rav Shimi bar Ashi: The halakha in all these halakhot is as Rabbi Abba sent to Rav Yosef bar Ḥama. Ravina said to Rav Ashi: What about the statement with which Rav Naḥman disagreed, i.e., that a debt can be collected by taking the slaves the debtor left his heirs? Is the halakha in accordance with this ruling of Rabbi Abba as well, despite the principle that in monetary matters the halakha is in accordance with Rav Naḥman’s opinion? Rav Ashi said to him: We teach a different tradition, that Rabbi Abba’s statement rules that a creditor does not collect the debt from the slaves the debtor left his heirs, and that Rav Naḥman said the same.

The Gemara asks: But then what possibility does Mar Zutra exclude in ruling that the halakha is in accordance with Rabbi Abba’s statement?