2,805. Vowing Not to Benefit From Jews

Hilchos Nedarim 9:20

If someone vows not to benefit from those who rest on Shabbos, he may not benefit from Jews or Samaritans. If he vows not to benefit from those who make pilgrimage to Jerusalem, he may not benefit from Jews but he may benefit from Samaritans because he only intended those for whom it is a mitzvah to make a pilgrimage to Jerusalem. If someone vows not to benefit from the descendants of Noach, he may benefit from Jews because the term “descendants of Noach” is used specifically to refer to the people of other nations.

Hilchos Nedarim 9:21

If someone vows not to benefit from the descendants of Avraham, he may benefit from the descendants of Yishmael (i.e., the Arabs) and the descendants of Eisav (presumably the Romans). He is only prohibited to benefit from Jews because Genesis 21:12 says, “Your descendants will be called through Yitzchak,” and Yitzchak told Yaakov, “I will give you the blessing of Avraham” (Gen. 28:4).