2,656. Eating Things Unfit for Consumption

Hilchos Shevuos 5:4

The aforementioned halachos apply when a person takes an oath about something that’s not in his jurisdiction, such as if Reuven takes an oath that Shimon won’t go on a business trip, or that he won’t eat meat, etc. But let’s say that Reuven takes an oath that Shimon may not enter his home nor benefit from Reven’s property. If Shimon violates the oath by entering Reuven’s home and benefitting from his property without Reuven’s knowledge, Reuven is exempt because the oath was transgressed based on circumstances beyond his control. Shimon, on the other hand, is liable, for doing something that was prohibited to him. In this case, Reuven took only an oath vis-a-vis his own property. The same is true in all similar cases.

Hilchos Shevuos 5:5

If someone took an oath not to eat and he ate, but he ate or drank things that weren’t fit for consumption, he’s exempt. If he ate foods that are prohibited by the Torah, like an olive’s volume of neveila, treifa, swarming things or creeping things, he isn’t liable for violating an oath of expression. If he takes an oath to eat and he eats or drinks things that aren’t fit for consumption, or he partook from neveila, treifa, etc., he isn’t liable for a false oath of expression as he is considered to have fulfilled the terms of the oath to eat. Since they were significant to him, eating them is considered eating.