Nedarim 45b (מה:) — the Talmud in English

Mishna:

Partners

who entered into a partnership in one courtyard,

who vowed not to derive benefit from one another—

are forbidden to enter the courtyard

because the tanna of our Mishna maintains that “waiving one’s rights,” even mere passage, which is the slightest possible benefit, is also forbidden to one who is forbidden by a vow to derive benefit, as explained above, at the beginning of the chapter “There Is No Distinction.”

Rabbi Eliezer ben Ya’akov says:

The partners may enter the courtyard, because he maintains that “there is bereira.” That is, we say that when a partner enters

this

courtyard, it becomes clear that he

entered into

the portion

belonging to him, and when

the partner

enters,

the second one, the courtyard, it likewise becomes clear that he

entered into

the portion

belonging to him.

The first tanna, however, maintains that there is no bereira. Therefore, both of them are forbidden to enter the courtyard, since each one enters his fellow’s portion, and he has made his property forbidden to him. The Gemara below [46b] establishes that our Mishna is referring specifically to a courtyard that is not subject to division; that is, it is so small that neither of the partners can compel the other to divide the courtyard and this means that it does not measure four cubits by four cubits]. But if it is subject to division, according to everyone both of them are forbidden to enter the courtyard and the reason for this will be explained below].