Nedarim, Chapter Four, Mishnah Three
This mishnah continues to discuss what Shimon may do for Reuven who has sworn not to receive benefit from him. The first part of the mishnah discusses certain mitzvoth which might cost money. The second part deals with feeding those whom the person who cannot receive benefit has a responsibility to feed.
1) He may donate his terumah and his tithes with his consent.
2) He may offer up for him the bird sacrifices of zavim and zavoth and the bird sacrifices of women after childbirth, sin-offerings and guilt-offerings.
3) He may teach him midrash, halakhoth and aggadoth, but not Scripture, yet he may teach his sons and daughters Scripture
4) And he may support his wife and children, even though he is liable for their maintenance.
5) But he may not feed his beasts, whether clean or unclean.
a) Rabbi Eliezer says: he may feed an unclean beast of his, but not a clean one.
b) They said to him: what is the difference between an unclean and a clean beast?
c) He replied to them, a clean beast, its life belongs to heaven, but its body is his own; but an unclean animal its body and life belongs to heaven.
d) They said to him: The life of an unclean beast too belongs to heaven and the body is his own for if he wishes, he can sell it to a non-Jew or feed dogs with it.
Section one: If Reuven cannot receive any benefit from Shimon, Shimon may still donate Reuvens terumah and tithes, as long as Reuven consents. This could happen in two ways. First of all, Reuven could say that anyone who wants to donate his terumah or tithes may do so. Shimon may then take of Reuvens produce and donate it. Alternatively, Shimon may donate of his own produce as if it was Reuvens and thereby exempt Reuven from giving terumah or tithes. Reuven may not specifically tell Shimon to donate his terumah for then Shimon would be an agent of Reuvens, which is forbidden.
Section two: When a person is purified from having been a zav or a zavah (some type of gonorrhea), s/he must bring bird sacrifices. Similarly, after having given birth, a woman must bring bird sacrifices. After sinning, a person must bring either a sin-offering or a guilt-offering, depending upon the sin. The mishnah teaches that if Shimon is a kohen, and Reuven cannot receive benefit from him, Shimon may still offer up his sacrifices, because kohanim are agents of God and are not considered the agents of those whose sacrifices they are offering.
Section three: Shimon can teach Reuven midrash (explanation of Scripture), halakhah (mishnah) and aggadah (legends) because all of these are part of the oral Torah, and teachers of the oral Torah were not paid for their teaching. Therefore, Reuven is not receiving financial benefit. However, Shimon may not teach Reuven written Torah (Scripture) without receiving pay, because people customarily were paid for this. If Shimon forgoes his pay, Reuven will have received financial benefit. However, Shimon may teach Reuvens sons and daughters Scripture, for this is a commandment placed upon the father. Shimons helping Reuven fulfill a commandment is not considered financial benefit, even though in reality, Reuven is saving money. Note, that this mishnah implies that a parent is obligated to teach his child Torah, more than he is obligated to learn Torah himself.
Section four: Shimon may feed Reuvens family, even though Reuven is obligated to do so. This is because Shimon is not giving anything to Reuven.
Section five: There is a debate whether or not Shimon may feed Reuvens impure (unkosher) animal. All hold that he may not feed Reuvens clean (kosher) animal, because that is giving Reuven money which he eventually might consume. However, the unkosher animal will not be eaten. Rabbi Eliezer argues that the impure animals flesh, when it dies, returns to God, just as its life-force does as well. Since the flesh doesnt belong to its Jewish owner, Shimon may feed it and it is not considered direct benefit to Reuven. The other Sages argue that since Reuven may give the animal (its meat) to a non-Jew or feed it to a dog, by feeding it Shimon would be benefiting Reuven, and it is therefore prohibited.