It was an accident TB Shabbat 72

Up to now we have been discussing two categories of Shabbat violators. The first is the mazid, מזיד. He knows it is Shabbat and what he is doing is prohibited on Shabbat; nevertheless, he consciously violates the Sabbath. One of his punishments is kareit, כרת.The second category is the shogeg, שוגג. He knows that it is Shabbat but forgets what he is doing is prohibited. Or, he forgets it is Shabbat but he knows that what he is doing would be prohibited. This individual needs to bring a sin offering, חטאת . Today’s daf TB Shabbat 72 introduces a third category, mit’asek, מתעסק.

A mit’asek has in mind to do something absolutely permitted on Shabbat. In the course of doing that permitted action, he accidentally violates the Sabbath. A mit’asek is exempt from bringing any sacrifice. A modern example of this category would be a person walking up a flight of stairs and accidentally brushes against the wall and turns on or off a light (which is prohibited according to orthodox understanding of Jewish law). Of course, after providing an example of mit’asek, the Gemara sites a disagreement between Rava and Abaye.

“It was stated that amora’im disagreed with regard to the halakha in the following case: One who intended to lift a plant detached from the ground on Shabbat and mistakenly severed a plant still attached to the ground, which under other circumstances constitutes performance of the prohibited labor of reaping, is exempt from bringing a sin-offering for his mistaken act, since he did not intend to perform an act of cutting. One who performs an action unawares [mitasek], i.e., he had no intention to perform the act at all, incurs no liability whatsoever.

“One who intended to cut a detached plant and unwittingly severed a plant still attached to the ground, Rava said: He too is exempt. Abaye said: He is liable. The Gemara elaborates: Rava said that he is exempt because he did not intend to perform an act of prohibited severing. He intended to perform an action completely permitted on Shabbat. He had no misconception with regard to the halakhot of Shabbat. It was merely a mistaken act. And Abaye said that he is liable because he intended to perform a standard act of cutting. Since he intended to perform that act, and he carried out his intent, the Torah characterizes it as unwitting and not as unawares.” (Sefaria.org translation)

Rava contends that what he didn’t do what he intended. The person had no intention of cutting the plant attached to the ground; consequently he is exempt from bringing a sin offering. Abaye contends his intentions were to cut and he fulfilled his intentions; consequently he is liable for a sin offering.

Once again Rambam decides Jewish law in favor of Rava’s understanding. Mishnah Torah, sefer karbanot, Hilkhot Shiggigot, chapter 7 halkhah 11.