Eruvin 36b (לו:) — the Talmud in English

acquires an urban residence”! If it enters your mind that “the beginning of the day acquires the eruv”,

then, since at the beginning of the day it is no longer tevel,

if he said

“Let my eruv be placed with this”—

why has he said nothing?!

And you are compelled to say that the tanna of this Mishna holds that “the end of the day acquires the eruv,” and it is still tevel.

Rav Pappa said

and rejected this:

Even if you say that “the beginning of the day acquires the eruv,”

it is still not effective, because

we require a meal that is fit to be eaten “while it is still day,” and there is none;

for while it is still day on the eve of Shabbat, it is still tevel.

Mishna:

A person may stipulate concerning his eruv;

that is, a person may, if he wishes, place two eruvin: one at the end of two thousand cubits east of his home, and one at the end of two thousand cubits west of his home, and stipulate

and say:

If there come

tomorrow

gentiles from the east,

and I will need to flee from them toward the west, let my

eruv

acquire for me at twilight, so that I may flee

westward

of the city.

And if they come

from the west,

let my

eruv

acquire for me, so that I may flee

eastward.

And

if they come

(from both sides)

from this side and from that side—

this is the reading in the Mishnayot—

I will go wherever I wish.

That is, the eruv should acquire for me at twilight, so that I will go in whichever direction I wish to travel.

And if

they do not come, neither from here nor from there, I am like the people of my city!

The reason for the entire Mishna is that we say: “There is retroactive clarification” (yesh berera). It is possible to perform an act whose legal effect takes effect now, while the clarification of that effect will occur tomorrow. In this case, tomorrow it will become clear which eruv acquired residence for him now, at twilight.

Similarly, he may stipulate concerning his eruv and make it dependent upon the arrival of a Sage, because he wishes to travel beyond the Shabbat limit in order to study Torah from him, but he does not now know from which direction he will come. Tomorrow he will learn this through people who come from there to here [by means of a techum eruv that they will place], and he says:

If there comes

tomorrow

a Sage from the east—

my eruv is to the east.

And if he comes

from the west—

my eruv is to the west.

If he comes,

that is, if two Sages come, one

to here and

one

to here—

I will go wherever I wish.

If they do not come

neither here nor there—

I am like the people of my city!

Rabbi Yehuda says: If

two came, one from here and one from there, and

one of them was his teacher,

then, although he had said, “I will go wherever I wish,” we do not say that he may go wherever he wishes to go. This is because “we know about him that, at the time he acquired his eruv, his intention was to acquire for himself the eruv on the side of his teacher; it was only that he did not know from which of the two directions he would come, and now that he knows, let him go there” [the wording of Rashi].

But the first tanna holds that even if one of them was his teacher, he may go wherever he wishes.

And if both of them were his teachers—

even if one of them was his primary teacher [Tosafot]—

he may go wherever he wishes.

Gemara:

When Rabbi Yitzḥak came

from Eretz Yisrael to Babylonia, he brought a beraita with him, in which it

teaches

the entire Mishna

in the reverse manner

[it contains all the cases of the Mishna—in reverse]:

In the first clause, concerning one who places his eruv because of the gentiles, it is taught: He stipulates concerning his eruv that he will be able to go in the direction from which the gentiles are coming.

And in the latter clause, concerning one who places his eruv because of a Sage, it is taught: He stipulates that he will be able to go in the direction opposite the direction from which the Sage comes; if he comes from the east, his eruv will be to the west.

And we raise a difficulty:

The gentiles

of the Mishna are difficult in comparison with

the gentiles

of the beraita, and

the Sage

of the Mishna is difficult in comparison with

the Sage

of the beraita?!

And we answer:

The gentiles in the Mishna and the gentiles in the beraita are not difficult!

This

—the case in the Mishna, where he is fleeing from the gentiles—

concerns tax collectors

[tax farmers], from whom he is fleeing.

This

—the case in the beraita, where he goes out to meet them—

concerns the leaders of the city

[the heads of the city], whom he must go to appease or protest against. [Tosafot explained below, on page 82a, that this is a matter of mitzva [as one places an eruv only for the sake of a mitzva], since he is going for the needs of the people of his city and attending to public affairs.]

The Sage in the Mishna and the Sage in the beraita are not difficult: This

—the Sage whom the person making the eruv mentions in the Mishna—

concerns one who delivers a public lecture

[expounds publicly], which he wishes to hear.

And

this

—the Sage whom the person making the eruv mentions in the beraita—

concerns one who teaches the Shema

[teaches children to pray]. Two come: one is a Torah scholar who lectures publicly, and the other teaches children to pray. He wishes to go hear the Torah scholar who lectures publicly, and therefore he formulates his statement negatively: He does not wish to go toward the one who teaches them to pray, but rather toward the one who lectures publicly.

We learned in the Mishna:

Rabbi Yehuda says: If one of them was his teacher,

he goes to his teacher, and if both of them were his teachers, he may go wherever he wishes:

And we explain:

And the Rabbis,

who disagree—what do they hold?

At times he prefers the

Sage who is

his colleague, more than his teacher

[either because human nature is drawn toward unfamiliar faces, or because he is embarrassed to ask his teacher, while he is not embarrassed before his colleague, Meiri]. It is therefore proper to invoke retroactive clarification, for we say that yesterday, at the time he acquired the eruv, his intention was for his colleague and not for his teacher, since we now see that he wishes to go to his colleague and not to his teacher.

Rav said,

concerning the latter clause of Rabbi Yehuda’s statement, where both were his teachers:

The Mishna is not authoritative,

as it states, according to Rabbi Yehuda, that he may go wherever he wishes, and that his eruv takes effect as Shabbat begins according to what he will choose tomorrow on Shabbat!

The proof that it is not authoritative is

from a

beraita

that

was

taught by Ayo

[the name of a Sage]!

As Ayo taught: Rabbi Yehuda says: A person may not stipulate concerning two matters simultaneously,

saying: If one comes here and one comes there, I will go wherever I wish, because there is no retroactive clarification.

Rather, he may stipulate only concerning one, while he does not know from which direction he will come [Rashi].

And therefore he does not stipulate

except: If

a Sage comes to the east, my eruv is to the east, and if a Sage comes to the west, my eruv is to the west.

And we raise a difficulty:

But if one comes here and one here—

not?!

What is different about one coming here and one coming there, such that it is not

effective, because

there is no retroactive clarification? “For when it is clarified tomorrow, we say: Perhaps yesterday, when he acquired the eruv, his intention was not for this [Sage], but for the other one” [Rashi]. If so, even when he stipulates concerning one, not knowing from which direction he will come, so that his eruv will be

If so, even when he makes a condition regarding one Sage, not knowing from which direction he will come, namely, that his eruv shall be

to the east

if he comes from there tomorrow,

and

his eruv will be to the

west

if he comes from there tomorrow,

there is likewise no retroactive clarification. “For when he said east or west, his intention was likewise that it should take effect in one of them, and tomorrow it would become clear in which direction the Sage would come; we must treat it as though it became clear today, and the eruv took effect there at twilight” [Ritva].

Rabbi Yoḥanan said

Rabbi Yoḥanan said

in answer:

In the beraita taught by Ayo, it is not discussing a case in which, at twilight, it was uncertain from which direction the Sage would come. Rather, it is discussing a case in which

In the beraita taught by Ayo, it is not speaking of a case in which, during twilight, it was uncertain from where the Sage would come. Rather, it is speaking of a case in which

the Sage had already arrived “on that side, and the matter was intrinsically clear at the time he acquired the eruv; the eruv took effect immediately, on that side, but he did not know this. In any such case, one cannot say that there is retroactive clarification, and his coming the next day is merely the revelation of an existing fact” [Ritva].

And now we return to what Rav said, that our Mishna is not authoritative, since it teaches according to Rabbi Yehuda that there is retroactive clarification, on the basis of Ayo’s beraita in the name of Rabbi Yehuda.

And we raise a difficulty:

On the contrary,

let us say that

it is not authoritative

the beraita

taught

by

Ayo, on the basis of

the

Mishna?!

And we answer: It is not possible to reject the beraita,

for we have heard from Rabbi Yehuda—

elsewhere—

that he does not hold that there is retroactive clarification,

as Ayo taught in his name.

For

so

we learned

[it was taught]:

One who purchases

a barrel of

wine

[containing one hundred log],

from the Samaritans

[before the decree was issued concerning their wine, Rashi], and ordinarily Samaritans do not separate teruma and tithes, and he has no vessels into which to separate teruma and tithes;