Nedarim 3:11-4:1

Nedarim 3:11 If one says, “Konam that I do not benefit from the descendants of Noah,” he is permitted to benefit from Jews and prohibited to benefit from non-Jews. “That I do not benefit from the descendants of Abraham,” he is prohibited to benefit from Jews and permitted to benefit from non-Jews. “That I do not benefit from a Jew,” he may buy for a higher price and sell for a lower price (so he is not benefitting). “That a Jew does not benefit from me,” he may buy for a lower price and sell for a higher price, assuming that the other party is willing to go for such an arrangement. “That I do not benefit from them, nor they from me,” he may benefit from non-Jews. “Konam that I do not benefit from the uncircumcised,” he is permitted to benefit from uncircumcised Jews and prohibited to benefit from circumcised non-Jews. “Konam that I do not benefit from the circumcised,” he is prohibited to benefit from uncircumcised Jews and permitted to benefit from circumcised non-Jews. The intention of the term “uncircumcised” is non-Jews regardless of one’s actual circumcision status as seen in such verses as Jeremiah 9:25 (“the nations are uncircumcised”), I Samuel 17:36 (“this uncircumcised Philistine”) and II Samuel 1:20 (“the daughters of the uncircumcised”). Rabbi Elazar ben Azariah says that we see that the foreskin is detestable because Tanach always uses it when it wants to criticize the nations for their evil deeds, as in “the nations are uncircumcised.” Rabbi Yishmael says that circumcision is great because it was the basis of 13 covenants (the word bris – “covenant” – is used 13 times when referring to circumcision). Rabbi Yosi says that circumcision is great because it supersedes Shabbos. Rabbi Yehoshua ben Karcha says that circumcision is great because not even Moshe was spared for an hour because of it (referring to the incident in Exodus chapter 4). Rabbi Nechemya says that circumcision is great because it supersedes the prohibition against removing potential tzaraas (a spiritually-caused skin condition). Rebbi says that circumcision is great because, despite all the mitzvos that Avraham performed, he was not called “perfect” until he was circumcised, as per Genesis 17:1, “walk before Me and be perfect.” Not only that, God would not have created the world if not for circumcision, as per Jeremiah 33:25, “If not for My covenant day and night, I would have not established the laws of Heaven and Earth.”

Nedarim 4:1

The only difference between one who is prohibited by a vow from benefitting from his friend and one who is prohibited from food by a vow is access to the friend’s property and use of his non-food-related utensils. If a person is prohibited by a vow from eating from his friend, the friend may not lend him a sieve, a strainer, a millstone or an oven but he may lend him a shirt, a ring, a cloak, earrings and anything else not used to prepare food. In a place where the latter articles are typically rented, the one who vowed may not borrow them from his friend (because he benefits from the waived rental fee).