ONE WHO IS MUDAR MA'ACHAL
Mishnah: If Reuven is Mudar Hana'ah (he or Shimon vowed that Reuven will not benefit) from Shimon, and Levi is Mudar Ma'achal (vowed not to eat) from Shimon, the only difference between them is that Reuven may not walk through Shimon's property or borrow Kelim not used for food, but Levi may.
Gemara - Inference: Neither of them may borrow Kelim used for food.
Nedarim 32b - Mishnah: Shimon may not lend to Levi a sifter, grinder or oven, but he may lend to him cloaks and rings.
Gemara - Question: Why can't he lend these things? He vowed only not to eat from him!
Answer #1 (Reish Lakish): The case is, he said 'Hana'ah from your food is forbidden to me.'
Objection: If so, Levi should be forbidden to use wheat that Shimon chewed (to cure a wound, for this is benefit from Shimon's food)!
Answer #2 (Rava): The case is, he said 'Hana'ah (from you) that leads to (your - this is not in the text of the Rishonim) food is forbidden to me.'
Rav Papa: A bag or donkey to bring fruit, or even a basket, is considered benefit that leads to food.
Questions (Rav Papa): May Levi borrow Shimon's horse to ride on, or his ring to wear? May he walk through Shimon's property (to get to a banquet hall, or to look more distinguished and thereby receive a nicer portion)?
Answer (Mishnah): He may lend to him a cloak, nose-rings and rings.
Question: What is the case?
If Levi will not get a better portion because he is wearing them, obviously they are permitted!
Answer #1: Rather, Levi will get a better portion, and nevertheless Shimon may lend him.
Rejection (and Answer #2 to Question (11)): Really, Levi will not get a better portion;
The Reisha lists Kelim that he may not lend to him, so the Seifa lists Kelim that he may lend him (even though it is obvious).
Mishnah: Similarly, he may not lend to Levi any Keli not used for food in a place where such Kelim are rented.
Gemara - Inference: The Kelim in the Reisha may not be lent even where they are not rented (but are lent for free). Who is the Tana?
Answer (Rav Ada bar Ahavah): It is R. Eliezer (who forbids even Vitur, i.e. small benefits which people normally bestow for free, to a Mudar Hana'ah).
Rif and Rosh (Nedarim 11a and 4:1): The Mishnah is R. Eliezer, who forbids even Vitur. The case is, he said 'Hana'ah from you that leads to food is forbidden to me.': A bag or donkey to bring fruit, or even a basket, is considered benefit that leads to food. The questions about Drisas ha'Regel (walking through property) and borrowing a horse or ring to assist eating are not resolved.
Ritva (DH u'Makom): The Mishnah forbids lending things in a place where they are rented, i.e. for that use. If a Keli is rented for major uses but lent for small uses, he may borrow it for a small use.
Rambam (Hilchos Nedarim 6:1): If Reuven is Mudar from Shimon Hana'ah that leads to Shimon's food, he may not borrow from him a sifter, grinder, oven, or anything used for food. He may borrow rings and Kelim not used for food. He may not borrow a bag or donkey to bring produce.
Rambam (2): In a place where Kelim are not lent only rented, he may not borrow even Kelim not used for food. The following are forbidden due to Safek, therefore one is not lashed for them:
In a place where Kelim are not rented, to borrow Kelim not used for food, but by wearing them one is apt to benefit;
Drisas ha'Regel to get to a place where he will benefit.
Rambam (3): The only differences between one who is Mudar Hana'ah and one who is Mudar Ma'achal are Drisas ha'Regel and borrowing Kelim not used for food in a place where people lend them for free.
Rosh (ibid.): Our Stam Tana is R. Eliezer, who forbids even Vitur. Therefore, a Mudar Hana'ah may not borrow Kelim even where they are not rented. The Halachah follows a Stam Mishnah, therefore we follow R. Eliezer. Also, the Sugya of partners is like him
Question: In a Chatzer, even Chachamim (Nedarim 45b) forbid Drisas ha'Regel to partners who are Mudar Hana'ah from each other. R. Eliezer permits only because of Breirah; all forbid Drisas ha'Regel through the other's property.
Answer (R. Tam, citing Rosh, ibid.): Our Mishnah discusses Drisas ha'Regel in a valley in summer, which people are not Makpid about.
Question: Why does the Gemara say that our Mishnah is R. Eliezer? Perhaps it discusses a Chatzer or a valley in winter, which people are Makpid about, and it is even like Chachamim!
Answer (Rosh, ibid.): If so it would be forbidden even to one who is Mudar Ma'achal, for this is something that people rent. The question about a horse is in a case where it is lent for free, e.g. between friends.
Ran (Nedarim 33a DH Omar Rava): Some say that also in the conclusion, when he forbade 'Hana'ah that leads to food', he may not use wheat that Shimon chewed to cure a wound. This is wrong. Rather, if he forbade Shimon's 'Ma'achal (food)', only eating his food is forbidden. If he forbid 'Hana'ah from your food', also using Shimon's chewed wheat to cure a wound is forbidden, but he may borrow a sifter (or grinder...) If he forbid 'Hana'ah that leads to food', this forbids eating and borrowing a sifter..., but chewed wheat is permitted for a cure.
Shulchan Aruch (YD 221:1): If Reuven is Mudar Hana'ah from Shimon, whether he or Shimon took the vow, Reuven may not pass through Shimon's field. This applies even to a valley in summer, when people are not particular about Drisas ha'Regel. He may not borrow any Keli from him.
Beis Yosef (DH Reuven): The Rosh and Ramban forbid Vitur, like R. Eliezer ben Yakov. It seems that the Rambam agrees, for he rules like our Mishnah. R. Chananel and R. Tam say that the Halachah does not follow R. Eliezer.
Shach (1): The Bach permits Reuven to pass through Shimon's field if this does not shorten his path, for he does not benefit, just like Shimon may pay Reuven's debt. This is wrong. Paying a debt is merely Gerama (causation). Here, he benefits through the walking itself. In the Seifa, when he forbade Hana'ah that leads to food, Rashi, the Rosh and the Ran explain that we forbid walking through Shimon's property to shorten the path to a banquet hall. In the Reisha (Mudar Hana'ah), they did not specify that Drisas ha'Regel is forbidden only if it is a shortcut. Even though in our Mishnah Rashi (DH Ela) says that Drisas ha'Regel is a shortcut, he does not mean that it depends on this. The Shulchan Aruch (Sof Siman 4) forbids Drisas ha'Regel even when it is not a shortcut.
Shulchan Aruch (ibid.): If he forbid his 'Ma'achal', only eating his food is forbidden. If he forbid 'Hana'ah from your food', also using Shimon's chewed wheat for a cure is forbidden, but he may borrow a sifter. If he forbid 'Hana'ah that leads to food', eating is forbidden, chewed wheat for a cure is permitted, but he may not borrow anything normally rented or anything connected with food. He may not use Shimon's horse or walk through Shimon's property to get to a banquet hall, or wear Shimon's ring there. Shimon may not buy things Reuven needs for a meal,
Taz (4): The Yerushalmi asked whether or not Shimon may buy things Reuven needs for a meal. Why wasn't this clear from the previous laws? One might have thought that we forbid only things that Reuven cannot do for himself.
Shulchan Aruch (ibid.): Reuven may not warm himself through Shimon's bread.
Taz (4): This belongs above, when he forbade 'Hana'ah from your food'.
Rema: A hatchet to chop wood for cooking is called benefit that leads to food, but a hatchet for weeding is permitted.
Shach (5): The Yerushalmi permits to borrow bowls and cups. They hold food, but they do not improve the food.
Rebuttal (Korban ha'Edah Nedarim 13a DH Ein): The Yerushalmi permits these because it establishes the Mishnah when he forbid 'Hana'ah from your food.' The Bavli establishes the Mishnah when he forbid 'Hana'ah that leads to food', therefore even bowls and cups are forbidden.
Defense (Keren Orah Nedarim 33a DH Rava): The Yerushalmi permits these even though it holds that 'Hana'ah from your food' forbids Hana'ah that leads to food!