39 Nedarim 4/1-4

(1) There is no [difference] between one who vows [not to] benefit from his friend, and one who vows [not to benefit] from his [friend's] food except for walking [in his field] and [borrowing his] utensils which are not used for food. One who vows [not to benefit] from his friend's food may not borrow a sifter or a sieve or a mill or an oven, but may borrow a robe or a ring or a garment or nose rings or anything that [people] don't make food in. In a place where they rent items similar [to the one he wants to borrow] - it is forbidden [to borrow them].

(2) One who vows [not to] benefit from his friend may pay his shekel [tax due to the Temple], may pay off his [friend's] debt, and may return his lost object. In a place where they pay a reward [for returning lost items], he must forfeit the benefit [he would have derived] as a hallowed offering [to the Temple].

(3) And [the one who vowed not to benefit from his friend] may separate his Teruma and his tithes with his [friend's] permission, and may offer his bird offerings [due to being] zav or zava [states of impurity for men and women after night emissions] or [having given] birth, his sin-offering, and his guilt-offering; one may also teach [the friend] Midrash, laws and lore, but may not teach him Scripture - one may, however, teach his sons and his daughters Scripture, and may feed his wife and his sons, even though he [himself] is responsible for their food. But he may not feed his animal, whether it be kosher or non-kosher. Rabbi Eliezer says: "He may feed his non-kosher [animal] but he may not feed his kosher [animal]". [The Sages] said to him: "What is the difference between kosher and non-kosher [animals, regarding this law]?" He responded to them: "Because a kosher [animal], its soul belongs to heaven and its body is his [the owner's], whereas a non-kosher [animal], [both] its soul and body belong to heaven." They responded [back] to him: "Even [in the case of a] non-kosher [animal], its soul belongs to heaven and its body is his, for if he wanted to, surely he could sell [the body] to non-Jews or feed it to his dogs."

(4) One who vows [not to] benefit from his friend and comes to visit him [when he is sick], [should] stand, but not sit. And one may heal his [friend’s] body, but not his assets [livestock]. And one may bathe with him in a large bathhouse, but not in a small one. And he may sleep with him in a bed. Rabbi Yehuda says: "[one may sleep in the same bed as the friend] during the summer, but not during the winter, because [during the winter] he will benefit from him." They may sit together on [the same] bed, and one may eat with him at the [same] table, but not from the main dish. However, one may eat [together] from a plentiful main dish. One may not eat with him from a trough which is [put] before workers, and may not work together in the same row [in a field] - these are the words of Rabbi Meir. But the Sages claim that one may work [together as in the same row, so long as each one works] far away [from the other].