between these amora’im parallels the disagreement between Rabbi Yehuda ben Beteira and the Rabbis? As we learned in a mishna (27a): If one took an oath to refrain from performing a mitzva and he did not refrain, he is exempt from bringing an offering for an oath on an utterance. If one took an oath to perform a mitzva and he did not perform it, he is also exempt, though it would have been fitting to argue that he is liable to bring the offering, in accordance with the statement of Rabbi Yehuda ben Beteira. As Rabbi Yehuda ben Beteira said: What? If, with regard to an oath concerning an optional matter, for which one is not under oath from Mount Sinai, he is liable for breaking it, then with regard to an oath about a mitzva, for which he is under oath from Mount Sinai, is it not logical that he would be liable for it?

The Rabbis said to him: No, if you said that one is liable for breaking an oath concerning an optional action, where the Torah rendered one liable for a negative oath not to perform it like for a positive oath to perform it, shall you also say one is liable for breaking an oath concerning a mitzva, where the Torah did not render one liable for a negative oath like for a positive oath? If one takes an oath to refrain from performing a mitzva and he did not refrain, he is exempt.

The Gemara asks: Shall we say that Rav states his opinion in accordance with that of Rabbi Yehuda ben Beteira, who holds that one can be liable for an oath that cannot be inverted, and Shmuel states his opinion in accordance with that of the Rabbis, who hold that one can be liable only if the oath can be inverted?

The Gemara rejects this: Everyone, i.e., both Rav and Shmuel, agrees with regard to the opinion of Rabbi Yehuda ben Beteira that one is liable if he took an oath that so-and-so performed an action that he did not in fact perform. The Gemara explains: Now, given that Rabbi Yehuda ben Beteira does not require that it be possible to invert a negative oath to a positive oath, does he require that it be possible for an oath to refer to the future as well as to the past? Shmuel explained that the reason one is not liable for an oath that so-and-so threw a stone into the sea is that it cannot be inverted to address the future, in other words: So-and-so will throw a stone into the sea, as that is not under the oath taker’s control.

When they disagree it is with regard to the opinion of the Rabbis: Shmuel holds like the Rabbis, that one is exempt in the case of an oath that cannot be inverted. Accordingly, Shmuel ruled that one who takes an oath that so-and-so threw an item is exempt from bringing an offering if it is found that the statement was false. And Rav holds that the Rabbis do not deem one liable in the case of an oath that cannot be inverted from negative to positive or vice versa, as it is written explicitly: ''Or if anyone take an oath clearly with his lips to do evil, or to do good'' (Leviticus 5:4). But with regard to the requirement that it be possible to invert an oath referring to the future to refer to the past or vice versa, which is derived from an amplification of the meaning of the verses, the Rabbis deem one liable, as they do not accept the derivation.

Rav Hamnuna raises an objection to Shmuel’s opinion from a mishna (29b): If one said: I did not eat today, or: I did not don phylacteries today, and another said to him: I administer an oath to you that your statement is true, and the original speaker said: Amen, he is liable for breaking an oath on an utterance if his statement was false, as responding amen to an oath administered to oneself is equivalent to stating the oath explicitly. Granted, he is liable in the case where he said: I did not eat, since it also would have been possible for him to take an oath saying: I will not eat, but in the case where he said: I did not don phylacteries, would it have been possible for him to take an oath saying: I will not don phylacteries, and in doing so abrogate a positive mitzva?

He, Rav Hamnuna, raises the objection and he resolves it: The tanna teaches this mishna disjunctively, referring to two different cases. When he teaches that one is liable for taking the oath: I did not eat, it refers to one’s liability to bring an offering. When he teaches liability for the oath: I did not don phylacteries, it refers to one’s liability to receive lashes for taking a false oath. This liability does not require that it be possible to invert the oath to refer to the future.

Rava also raises an objection to Shmuel’s opinion from a mishna (see 29a): Which oath is an oath taken in vain? It is when one takes an oath to deny that which is known to people to be true, and, for example, says about a stone column that is in such and such a place that it is made of gold. And Ulla says that the phrase: Known to people, in the mishna is referring to when it is a fact that is known to three people. The Gemara explains the objection to Shmuel’s opinion: The reason he is liable for taking an oath in vain is due to the fact that his oath contradicted a fact known to three people. But if it is not known, he violates the prohibition of taking a false oath on an utterance. Given Shmuel’s opinion, why should he be liable? Isn’t it impossible to invert the oath to make it about the future, saying: That column will be of gold?

He raises the objection and he resolves it. When the fact is known to three people, the one who takes an oath denying it violates the prohibition of taking an oath in vain. If it is not known, then he violates the prohibition of taking a false oath, for which he receives lashes if he did so intentionally. Nevertheless, he is not liable to bring an offering for falsely taking an oath on an utterance, since this oath cannot be inverted to be about the future.

§ Abaye said: And Rav, who holds one liable for an oath on an utterance even if it cannot be inverted to refer to the future, concedes in a case where one says to another: On my oath I know testimony that is relevant to you, and it is found afterward that he did not know testimony that was relevant to him, that in that case he is exempt from bringing an offering for an oath on an utterance. The reason is that it is not in the category of an oath that could be inverted to the negative oath of: I do not know testimony that is relevant to you, as that oath would be an oath of testimony, rather than an oath on an utterance. The Torah states: ''And if anyone sin, in that he hears the voice of adjuration, he being a witness, whether he has seen or known, if he do not utter it, then he shall bear his iniquity'' (Leviticus 5:1). One is liable to bring an offering for an oath of testimony if he takes an oath falsely denying that he has knowledge of testimony in a monetary matter.

But if he takes an oath saying: I knew testimony that is relevant to you, or: I did not know testimony that is relevant to you, the halakha is subject to the dispute between Rav and Shmuel. Similarly, if he took an oath saying: I testified, or: I did not testify, whether or not he is liable to bring an offering for an oath on an utterance depends on the dispute between Rav and Shmuel. In these cases, the oaths cannot be inverted from the past to the future and are also not oaths of testimony, since they do not involve the refusal to testify.

The Gemara says: Granted, according to the opinion of Shmuel, who says that an oath about a matter that cannot be inverted to refer to the future is one for which one is not liable when it refers to the past, it is for that reason the Merciful One removed an oath of testimony, which cannot be inverted, from the category of an oath on an utterance and legislated it in a separate verse (see Leviticus 5:1). But according to the opinion of Rav, for what halakha did the Merciful One remove it from the category of an oath on an utterance and relate to it as a distinct category? Every oath of testimony is a case of an oath on an utterance and there is no need to relate to it as a special case.

The Sages said before Abaye: An oath of testimony is singled out, according to Rav, in order to render one who takes it falsely liable to bring two sliding-scale offerings for it, one for a false oath on an utterance and one for a false oath of testimony.

Abaye said to them: You cannot say that one who takes a false oath of testimony is liable to bring two offerings, as it is taught in a baraita with regard to the sliding-scale offering that is brought for both an oath of testimony and an oath on an utterance: The verse states: ''And it shall be, when he shall be guilty in one of these things'' (Leviticus 5:5). By inference, for one of the sins that render one liable to bring a sliding-scale offering you may deem him liable, but you may not deem him liable for two.

The Gemara asks: And if this is so, then according to Abaye’s understanding of the opinion of Rav, for what halakha did the Merciful One remove an oath of testimony from the category of an oath on an utterance and relate to it as a distinct category?

The Gemara answers: An oath of testimony is singled out, as it is taught in a baraita: For every other one of the prohibitions for which one is liable to bring a sliding-scale offering, it is stated in the verse: ''And it is hidden from him'' (see Leviticus 5:2–4), and here, with regard to the oath of testimony, the phrase: And it is hidden from him, is not stated. This serves to render one liable to bring an offering for taking a false oath of testimony intentionally like one who is liable for doing so unwittingly.

The Sages said to Abaye: Say that the oath of testimony was singled out for a different reason: When he takes a false oath of testimony intentionally he is liable to bring only one offering but when he does so unwittingly, he is liable to bring two, one for an oath of testimony and one for an oath on an utterance.

Abaye said to them in response: Is this not what they said in a baraita with regard to the verse about the sliding-scale offering: ''When he shall be guilty in one of these things'' (Leviticus 5:5)? By inference, for one of the sins that render one liable to bring a sliding-scale offering you may deem him liable, but you may not deem him liable for two? And since one does not bring an offering for an intentional false oath on an utterance, if the verse is referring to a case where he intentionally took a false oath of testimony, how could there be a case where one is liable to bring two offerings such that this case needs to be excluded? Consequently, the verse must be referring to a case where he took the oath unwittingly, and it teaches that nevertheless, one brings only one offering for each violation.

Rava said in response to the question posed by the Sages: There is no need to derive from a verse that one is liable to bring only one offering for a false oath of testimony. Since an oath of testimony is a matter that was included in a generalization, i.e., the general principle of an oath on an utterance, and it was singled out to teach a new matter with regard to it, you have only the new matter alone to consider. Since an oath of testimony is singled out in that it applies only to potential witnesses in the context of a court, a case of an oath of testimony ceases to be included under the rubric of an oath on an utterance.

The Gemara asks: Should one understand by inference that Abaye holds that in cases of an oath of testimony, the oath on an utterance still exists in principle? One does not bring two offerings because of the halakha derived from the verse, but if for some reason the oath of testimony does not take effect, one may still be liable for an oath on an utterance.

But didn’t Abaye say that Rav concedes that one is exempt from bringing an offering for an oath on an utterance in a case where one says to another: On my oath I know testimony that is relevant to you, and it was found that he did not know testimony that was relevant to him? In that case he is exempt from bringing an offering for an oath on utterance, since it is not an oath that could be inverted to the negative oath: I do not know testimony that is relevant to you, as that oath would be an oath of testimony rather than an oath on an utterance.

The Gemara answers: Abaye retracted that opinion. And if you wish, say instead that