Therefore, Abaye teaches us that this is not so. The Gemara raises an objection from a baraita: What is an unwitting violation of an oath on a statement relating to the past? What is an example of one who unwittingly swore falsely with regard to an incident that occurred in the past? It cannot be a case where he forgot the incident, as in that case he is exempt from bringing an offering. It is a case where if he said: I know that taking this false oath is prohibited, but I do not know whether or not one is liable to bring an offering for swearing falsely, he is liable to bring an offering for an unwitting transgression. Apparently, with regard to an oath on a statement, unwitting with regard to the sacrifice renders the action unwitting. The Gemara rejects this: In accordance with whose opinion is this mishna? It is the opinion of Munbaz. In his opinion, one who commits a transgression while unaware whether or not one is liable to bring an offering if he performs that transgression unwittingly is considered to have performed the transgression unwittingly.

There is another version of the discussion of Abaye’s statement where, after quoting the halakha with regard to an oath on a statement, the question was raised: In accordance with whose opinion is this mishna? If you say it is in accordance with the opinion of Munbaz, that is obvious: Now, if throughout the entire Torah where there is no novelty in the obligation to bring an offering, he said that unwitting with regard to an offering is considered unwitting; here, where there is a novelty and the offering in the case of an oath on a statement is more significant than other sin-offerings, certainly unwitting with regard to the offering should be considered unwitting. Rather, is it not the opinion of the Rabbis, and this is a conclusive refutation of the opinion of Abaye? The Gemara concludes: Indeed, it is a conclusive refutation.

And Abaye said: Everyone agrees with regard to teruma that one is only liable to add a payment of one-fifth the value of the teruma for eating it unwittingly if he is unwitting with regard to its prohibition. The Gemara asks: To whose opinion is Abaye referring in the phrase: Everyone agrees? Certainly, it is the opinion of Rabbi Yoḥanan. Even though, in general, he holds that unwitting with regard to karet is sufficient to render the action unwitting, the case of teruma is different. The Gemara asks: In the case of teruma, it is obvious that he would agree. When Rabbi Yoḥanan says that one need not be unwitting with regard to the prohibition, it is in a case where there is a prohibition punishable by karet; however, here, where there is no punishment of karet, Rabbi Yoḥanan would not say so. The Gemara answers that nonetheless Abaye introduced a novel element: Lest you say that since one who intentionally eats teruma is subject to death at the hand of Heaven, perhaps death stands in place of karet. And where he was unwitting with regard to the punishment of death for this sin, he should also be liable to pay the added fifth as one who performed the transgression unwittingly because his case is analogous to one who is considered unwitting due to lack of awareness of karet. Therefore, Abaye teaches us that it is not so. Rava said: Indeed, death stands in place of karet and the added one-fifth stands in place of a sacrifice. One who is unwitting with regard to death at the hand of Heaven and the added fifth has the same legal status as one who is unwitting with regard to karet and an offering.

Rav Huna said: One who was walking along the way or in the desert, and he does not know when Shabbat occurs, he counts six days from the day that he realized that he lost track of Shabbat and then observes one day as Shabbat. Ḥiyya bar Rav says: He first observes one day as Shabbat and then he counts six weekdays. The Gemara explains: With regard to what do they disagree? One Sage, Rav Huna, held: It is like the creation of the world, weekdays followed by Shabbat. And one Sage, Ḥiyya bar Rav, held: It is like Adam, the first man, who was created on the sixth day. He observed Shabbat followed by the six days of the week. The Gemara raises an objection to the opinion of Ḥiyya bar Rav from a baraita: If a person was walking along the way and does not know when Shabbat occurs, he observes one day for every six. What, does this not mean that he counts six and then observes one day in accordance with the opinion of Rav Huna? The Gemara rejects this: No, it could also mean that he observes one day and then counts six.

The Gemara asks: If so, if that is what the baraita meant, why employ the phrase: He observes one day for six? It should have stated: He observes one day and counts six. And furthermore, it was taught in a baraita: If one was walking along the way or was in the desert, and he does not know when Shabbat occurs, he counts six days and observes one day. That is a conclusive refutation of the opinion of Rabbi Ḥiyya bar Rav. The Gemara concludes: Indeed, it is a conclusive refutation of the opinion of Ḥiyya bar Rav.

Rava said: The person who lost track of Shabbat and treats one day a week as Shabbat, each day he makes enough food to sustain himself, except for that day which he designated as Shabbat. The Gemara asks: And on that day let him die? Rather, it means that the day before he makes twice the amount of food that he prepared on the other days to sustain him for that day and the following day. The Gemara asks: And perhaps the day before was actually Shabbat? In that case, not only did he perform labor on Shabbat, but he also performed labor on Shabbat in preparation for a weekday. Rather, on each and every day he makes enough food to sustain himself for that day, including on that day that he designated as Shabbat. And if you ask: And how is that day which he designated as Shabbat distinguishable from the rest? It is distinguishable by means of the kiddush and the havdala that he recites on that day.

Rava said: If he had partial knowledge of the day on which he left, i.e., he does not recall what day of the week it was but he does recall the number of days that passed since he left, every week he can perform labor throughout the day of his departure, since he certainly did not leave his house on Shabbat. The Gemara asks: That is obvious, and what novel element was introduced here? The Gemara answers: Lest you say, since he did not leave on Shabbat, he also did not leave on Friday, and this person, even if he left on Thursday, should be permitted to perform labor for two days, the eighth day and the ninth day from his departure, the same day of the week that he left and the following day. Therefore, Rava teaches us that at times one finds a convoy and happens to leave on a journey even on Friday. Therefore, he is not permitted to perform labor on the day of the week following the day of his departure.

We learned in the mishna that there is a difference in halakha between one who knows the essence of Shabbat and one who does not know it. The Gemara asks: From where in the Torah are these matters derived? Rav Naḥman said that Rabba bar Avuh said: Two verses are written. One states: “And the children of Israel observed the Shabbat, to perform the Shabbat through their generations, an everlasting covenant” (Exodus 31:16). And it is written: “And you shall observe My Shabbatot and you shall revere My Sanctuary, I am God” (Leviticus 26:2). How is it that Shabbat is in the singular in one verse, while in the other it is in the plural [Shabbatot]? It should be understood as follows: “And the children of Israel observed the Shabbat”: One observance for multiple Shabbatot. If one commits several transgressions, in certain cases he is only liable to bring one sacrifice. “And you shall observe My Shabbatot”: One observance for each and every Shabbat. In certain cases, one is liable to bring a sin-offering for each time that he unwittingly desecrated Shabbat.

Rav Naḥman bar Yitzḥak strongly objects: On the contrary, the opposite is reasonable. “And the children of Israel observed the Shabbat”: One observance for each and every Shabbat. “And you shall observe My Shabbatot”: One observance for multiple Shabbatot. In any case, Rav Naḥman bar Yitzḥak also holds that the halakha of our mishna is derived from comparing and contrasting these two verses.

We learned in the mishna that there is a difference between one who is aware that the day is Shabbat and performs labor and one who forgets the essence of Shabbat and performs prohibited labors.