2,785. Prohibiting Benefit to Kohanim and Leviim

Hilchos Nedarim 7:11

If someone prohibited kohanim or Leviim to benefit from his property, they may still come and take trumah and tithes against his will. If he prohibits specific kohanim or Leviim to benefit from his property, they must observe his ban and he gives trumah and tithes to different kohanim and Leviim. The same is true when it comes to vows prohibiting needy people and the portions that are given to the needy.

Hilchos Nedarim 7:12

Let’s say that person A is prohibited to benefit person B and person B has nothing to eat. In such a case, person A can go to a shopkeeper and say: “Person B is prohibited to benefit from me and I don’t know what to do.” The shopkeeper can then bring food to person B and accept payment from person A. (Why is this permitted? See the next halacha.)