What is the case of an unwitting oath on an utterance referring to the past, for which one is liable to bring an offering? If it is a case where he knows when he takes the oath that it is not true, then he is an intentional taker of a false oath and may not bring an offering. If it is a case where he did not know at the time of taking the oath that what he was saying is not true, then he is a victim of circumstances beyond his control, and is exempt from bringing an offering.

Rav Naḥman said to him in answer to his question: It is a case where the one taking the oath says: I know that taking this oath is prohibited, but I do not know if one is liable to bring an offering for it or not. Since he does not know the full implications of his action, it is regarded as unwitting, and he may still bring an offering to atone for it.

Rava asked Rav Naḥman further: In accordance with whose opinion do you answer in this way? Is it in accordance with the opinion of Munbaz, who says: Lack of intention with regard to the offering, i.e., ignorance as to whether one’s action renders one liable to bring an offering, is regarded as lack of intention? There is a dispute between Munbaz and the Rabbis in tractate Shabbat (69a–b) with regard to one who knows that a particular action desecrates Shabbat but does not know that it renders one liable to bring a sin-offering. Munbaz holds that even one who is merely ignorant of the liability to bring an offering is deemed an unwitting sinner who brings a sin-offering to atone. The Rabbis disagree and deem him unwitting only if he is unaware that the action is prohibited.

Rav Naḥman explains: You may even say that this explanation accords with the opinion of the Rabbis. The Rabbis disagree with the opinion of Munbaz only with regard to all typical cases in the entire Torah for which one is liable to bring a sin-offering, where that liability is not a novelty. But here, with regard to oaths, it could be said that bringing a sin-offering is a novelty, since there is a principle that we do not find in the entire Torah another example of a simple prohibition for which one brings an offering for its unwitting violation.

Rav Naḥman continues: The reason for this principle is that we derive for which prohibitions one brings a sin-offering from the prohibition of idol worship, where one is liable to receive karet for an intentional violation and one is liable to bring a sin-offering for an unwitting violation. And yet here, in the case of the oath, one brings a sin-offering even though intentional violation of the prohibition is not punishable by karet. Given the novelty of the offering for an oath on an utterance, even the Rabbis would agree that ignorance of the fact that one is performing an action for which the Torah legislates an offering is sufficient for one to be regarded as unwitting and liable to bring a sliding-scale offering.

Ravina asked Rava: If one took an oath concerning a certain loaf, rendering himself prohibited from eating it, and later his life is in danger due to his not eating it, what is the halakha? Is he liable to bring an offering in atonement for eating it?

Rava responded: If his life is in danger, let the Master permit him to eat, as saving his life overrides the prohibition; he is considered a victim of circumstances beyond his control and does not need to atone at all. Ravina said: Rather, the question is this: With regard to one who is suffering from hunger and who ate it unwittingly, i.e., he forgot the prohibition generated by the oath, although had he known, he would still have eaten this loaf of bread intentionally due to his hunger, what is the halakha?

Rava said to him: We learn in a baraita: One who, had he known that his action was prohibited, would have withdrawn from sinning due to his knowledge, brings an offering for his unwitting sin; but one who would not have withdrawn from sinning due to his knowledge does not bring an offering for his unwitting sin. Since he would have eaten anyway, he does not bring an offering.

§ Shmuel says: Even after one decided to take an oath, he needs to express it with his lips for it to take effect, as it is stated in the verse: “Or if anyone take an oath clearly with his lips to do evil, or to do good” (Leviticus 5:4).

The Gemara raises an objection from a baraita: The verse states that one takes an oath “with his lips,” but not with his heart. From where is it derived that one who decided in his heart to take an oath is liable to bring an offering for an oath on an utterance? The verse states: “Whatsoever it be that a man shall express with an oath” (Leviticus 5:4).

The Gemara points out: This baraita is difficult in itself. You said: “With his lips,” but not with his heart, and then you said: From where is it derived that one who decided in his heart to take an oath is liable? There seems to be a contradiction within the baraita concerning the halakha where one did not express the oath.

Rav Sheshet said: This is not difficult; this is what the baraita is saying: One takes an oath “with his lips” and does not take an oath when he merely decided in his heart to express with his lips but has not yet actually expressed the oath verbally. From where is it derived that one who simply decided in his heart to take an oath without the intention of stating it with his lips is liable? The verse states: “Whatsoever it be that a man shall express with an oath” (Leviticus 5:4).

The Gemara challenges: But according to the opinion of Shmuel, this baraita nevertheless poses a difficulty, as it indicates that an oath that was not expressed verbally takes effect.

Rav Sheshet said: Resolve the difficulty and say the baraita like this: One takes an oath “with his lips,” but does not take an oath where he decided in his heart to express an oath prohibiting wheat bread and he instead expressed an oath about barley bread. From where is it derived that he is liable where he decided in his heart to express an oath about wheat bread and expressed his oath about bread without specifying? The verse states: “Whatsoever it be that a man shall express with an oath.”

The Gemara raises an objection to the opinion of Shmuel from a baraita: The verse states: “That which is gone out of your lips you shall observe and do; according as you have vowed freely to the Lord your God, even that which you have promised with your mouth” (Deuteronomy 23:24). From here I have derived only a case in which he expresses with his lips. From where do I derive a case where he decided only in his heart? The verse states in the context of the contributions to the building of the Tabernacle: “And they came, both men and women, as many as were willinghearted, and brought nose rings, and earrings, and signet rings, and girdles, all jewels of gold” (Exodus 35:22). The fact that the verse describes those who contributed as willinghearted indicates that one becomes liable via a non-verbal decision.

The Gemara answers: The case there, of contributions to the Tabernacle, is different, as it is written: “As many as were willinghearted.” This halakha is stated only in the context of contributions to the Tabernacle, not in the context of oaths.

The Gemara suggests: And let us learn from it that in general, oaths can be taken via a non-verbal decision.

The Gemara rejects this: One cannot extrapolate from the fact that the non-verbal consecrations to the Tabernacle were effective, because teruma, which can be separated non-verbally, and donating consecrated items are two verses that come as one, i.e., they are both instances where a non-verbal commitment is sufficient, and any two verses that come as one do not teach their common element to apply to other cases.

The Gemara asks: This works out well according to the one who says that two verses that come as one do not teach their common element, but according to the one who says that they do teach their common element, what can be said?

The Gemara answers: The two contexts here are non-sacred items, i.e., oaths, and consecrated items, donations to the Tabernacle and teruma, and we do not derive halakhot concerning non-sacred items from halakhot concerning consecrated items.