Pesachim 47 - Since
If one bakes bread close to the end of a holiday, essentially for the following weekday, then he is liable to punishment - says Rav Chisda. One is not allowed to cook on a holiday other than for the needs of this holiday.
However, Rabbah says that since guests may happen to visit him just before the end of the day, and then he will feed this bread to them, therefore even now he can be considered baking for a valid purpose and thus he is not liable.
This principle of "since" has so many implications that it gets a special name, "since", or "hoil" in Hebrew. Therefore Rav Chisda and Rabbah begin to argue about this principle, since Rav Chisda does not accept it, while Rabbah does. For example, they discuss the following case.
One can plow a single furrow and transgress eight times because of that. How so? - Firstly, he plows with an ox and a donkey tied together. Then, they are consecrated as sacrifices. He is sowing wheat in a vineyard. It is the seventh year (Shmita) when plowing is forbidden; moreover, he is doing this on a holiday. He is a kohen and a nazirite, but plows in a cemetery, which neither a kohen nor a nazirite can visit. That’s eight. However, if the principle of "since" is true, then it should be only seven transgressions, and he should not be liable for plowing itself, because with the act of plowing he produces dust, which can be used to cover the blood of a bird, a requirement of kosher slaughter. And "since" he can use the dust for this, it should not be counted!
That is a question that Rav Chisda asked of Rabbah. However, Rabbah answered that he is plowing rocky ground, with no dust. And the discussion continued.
Art: Plowed Field by Edgar Degas