Nedarim 47b — the Talmud in English

Or perhaps,

the reason for the prohibition in our Mishna is

because exchanges are considered like growths,

and they were prohibited by rabbinic decree upon the one who himself made the exchange; and if so,

it is no different

if he prohibited them to himself, and he made the exchange,

and it is no different

when he prohibited them to his fellow, and his fellow made the exchange—

his fellow—

they become prohibited?

Rav Aḥa bar Minyomi said: Ta shma: One who says to his wife, “Konam that I benefit from you,” borrows

money for her needs,

and creditors come and collect

from the husband.

For although her husband’s property was prohibited to her, his property nevertheless remained liened for her needs; therefore, the creditors return and collect from the husband.

And if the law is that exchanges are considered like growths,

why do the creditors collect?

For we are certain that the lender intended to lend to the woman on the understanding that she herself would repay him, and he did not give it to her on the understanding that he would collect the money from the husband. For what he lends to the woman is an exchange of the husband’s property; and if so, if he lends to her on the understanding that he will collect from the husband, he would thereby cause a prohibition, since she would benefit from an exchange of the husband’s property!

Rather, certainly he gave it to her on the understanding that he would collect from her herself; and why can he return and collect from the husband!?

Rather,

no—

because exchanges are not considered like growths,

and therefore it is indeed permitted to lend to her on the understanding that they will collect from the husband, since in the end she does not benefit from the husband’s property itself, but from its exchange!

And the Gemara rejects the proof:

Rava said: Perhaps it is only initially that it is not permitted,

that is, when one comes to exchange a prohibited item for a permitted one initially, it is prohibited, and the exchange becomes prohibited.

But if he did it—

he did it

[and if an exchange was made after the fact—it is permitted].

And therefore, here, at the time that she borrowed, when the money was not yet an actual exchange of a prohibited item, she was permitted to borrow and eat. And although afterward they collect from the husband, this is after the fact, for it is then that the money became an exchange for what she ate.

Rather, ta shma

from the Mishna in tractate Kiddushin:

One who betroths

a woman

with

fruit

of orla—

she is not betrothed.

And the reason is that it is prohibited to benefit from fruit of orla.

But if he

sold them and betrothed

a woman

with their proceeds—

she is betrothed.

And if the law is that exchanges are like growths, then why, when he betrothed her with the exchange, is she betrothed? For the exchange too should be prohibited for benefit!

And we reject this:

Here too, it is only initially that it is not permitted.

That is, initially it is indeed prohibited to benefit even from the exchange.

But if he did it

[and if he transgressed and benefited from them]—

he did it

[his act takes effect], because in truth the exchange is permitted.

Mishna:

If a person said to his fellow:

“I am a herem to you,”

that is, he shall be prohibited from benefiting from me, just as it is prohibited to benefit from a herem that a person devoted for the repair of the Temple — the ruling is that

the one prohibited by vow from receiving benefit

[from his fellow]

is prohibited

from benefiting from him.

And if a person said to his fellow:

“Behold, you are a herem to me,”

that is, I shall be prohibited from benefiting from you, just as it is prohibited to benefit from a herem—then

the one who makes the vow

[the one who said this]

is prohibited

from benefiting from his fellow.

And if he said to him:

“I am a herem to you

—a herem,

and you are to me

[that is, you too are a herem to me]”—then the ruling is that

both are prohibited.

That is, each one is prohibited from his fellow’s property.

And both are permitted with regard to something belonging to the “those who ascended from Babylonia,”

as the Gemara will explain below, because those who ascended from Babylonia made it ownerless for all Israel.