Maaseh Shabbos 3

If one forgets the main [idea of] Shabbos - he thinks that there is no mitzvah of Shabbos in the Torah.

He is only obligated to bring 1 korban Chatas - in the gemara (69b) it is learned out one "watching" [keeping the mitzvos of Shabbos] for many Shabboses, and a "watching" for each Shabbos, and it would make sense that when it writes one watching for many Shabboses it is referring to this type of case, where it is all one mistake, and the korban is brought to fix the mistake.

If one knows about Shabbos - that it talks about Shabbos in the Torah and it forbids doing the melachos.

And he did many different melachos on many Shabbosos - through forgetting that today is Shabbos. Since in the end it says, "one who knows it is Shabbos" it teaches us that the beginning case was regarding one who forgot it was Shabbos and he did many melachos on many Shabbosos and he was not aware in between [the weekly transgressions] that he had sinned/was sinning.

He is obligated [to bring a korban] for each Shabbos - and even though he did not know in between and it was all one mental lapse, we say that the days in between count as knowing, for it is impossible that he did not hear in between that this day is Shabbos just he did not remember that he had done melachos on that day and his original mistake was that he didn't realize that it was Shabbos, and this was made known to him [when he heard that that day was Shabbos] therefore each Shabbos is a separate mistake. Though in truth on the many melachos that he did each Shabbos he is not obligated more than the 1 [offering] for the entire Shabbos was one mistake, since he did not make a mistake about the melachos not existing, rather he knew they are forbidden, it was just that he didn't realize it was Shabbos.

One who knows that it is Shabbos and he does many melachos - not realizing that these actions are forbidden, he did them many times on many different Shabboses, he is obligated to bring a korban chatas for each main melacha, even though he repeated that offense on many Shabboses, it was all 1 mistake for he was not aware of it in between [the transgressions]. Regarding forgetting that today is Shabbos we say that he knew in between which divides the transgressions but regarding the melachos we don't say this, since the days of the week won't give him the knowledge unless he happens to learn those hilchos Shabbos during that week. Though in truth 1 chatas is not enough for each Shabbos since he forgot many melachos each Shabbos had many mistakes and in the gemara (70a) we learned: there are times that he is obligated for each one, and there are times that he's only obligated once for the whole Shabbos. It makes sense that the many obligations are for knowing that it is Shabbos but forgetting many melachos, since there are many mistakes, though forgetting about Shabbos and knowing the melachos is one mistake.

When the gemara talks about the parent melacha it is not coming to exclude the sub-category melachos for they are the same [get separate punishments] if they are from different parent melachos. Rather it is comign to exclude where one did 2 subcategory problems that are both part of the same parent melacha or the parent and subcategory of the same melacha in which case only 1 korban is required.

The Gemara raises another difficulty: But if he did not forget the essence of Shabbat, and he knows that today is Shabbat, what would the halakha be? Certainly he would be liable for each and every prohibited labor. If so, instead of teaching the halakha: One who knows that it is Shabbat and performs many labors on multiple Shabbatot is liable for each and every labor, let the mishna teach the halakha: One who knows the essence of Shabbat is liable for each and every labor that he performs and all the more so that one who is aware that today is Shabbat would be liable for each labor. Rather, when our mishna refers to forgetting, it is referring to a case where he knew and ultimately forgot. And the case described by Rav and Shmuel also has the same legal status as one who knew and ultimately forgot. And it was stated as follows: It was Rav and Shmuel who both said: Even a child who was taken captive among the gentiles and a convert who converted among the gentiles have the same legal status as one who knew and ultimately forgot, and they are liable to bring a sin-offering for their unwitting transgression, even though they never learned about Shabbat. And it was Rabbi Yoḥanan and Rabbi Shimon ben Lakish who both said: He is liable to bring a sin-offering specifically if he knew of the essence of Shabbat and ultimately forgot. However, a child who was taken captive among the gentiles and a convert who converted among the gentiles are exempt from bringing a sin-offering. They have the legal status of one who performed the prohibited labor due to circumstances beyond his control. The Gemara raises an objection from that which was taught in a baraita: They stated a significant principle with regard to the halakhot of Shabbat: One who forgets the essence of Shabbat, i.e., one who does not know that there is a mitzva of Shabbat in the Torah, and performs many prohibited labors on multiple Shabbatot is liable to bring only one sin-offering. How so? With regard to a child who was taken captive among the gentiles and a convert who converted among the gentiles and does not know the essence of Shabbat; and if he performed many prohibited labors on multiple Shabbatot, he is only liable to bring one sin-offering for all his unwitting transgressions. And he is liable to bring one sin-offering for all the blood he unwittingly ate before he learned of the prohibition; and one sin-offering for all the forbidden fat that he ate; and one for all the idolatry that he worshipped. And Munbaz, one of the Sages, deems him exempt from bringing any sacrifice.