MISHNA: The Sages stated a significant principle with regard to the halakhot of Shabbat: One who forgets the essence of Shabbat, i.e., one who is entirely ignorant of the mitzva of Shabbat according to Torah law, and performed numerous prohibited labors on multiple Shabbatot, is liable to bring only one sin-offering for all those labors when he becomes aware that those actions were prohibited. One who knows the essence of Shabbat but forgets which day is Shabbat, i.e., one who lost track of the days of the week, and performs numerous prohibited labors on multiple Shabbatot is liable to bring a sin-offering for each Shabbat when he becomes aware that he performed those actions on Shabbat. One who is aware that the day is Shabbat but temporarily forgot that certain labors were prohibited and performed numerous prohibited labors on multiple Shabbatot is liable to bring a sin-offering for each
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.