Talmud - Eruvin 20a עירובין כ׳ א׳

that the baraita teaches two types of tree; here too, then, you can say that it teaches two types of fence, and therefore no proof can be brought from this baraita.

And Abaye further inquired of Rabba: With regard to a courtyard, the open end of which interposed between the boards surrounding a well, what is the law with regard to carrying from inside the courtyard to the area between the upright boards, and from the area between the boards into the courtyard? Rabba said to him: It is permitted.

Abaye then asked him: And if two adjacent courtyards interposed between the boards surrounding a well, what is the law? Is it permitted to carry from inside them to the area between the boards, and vice versa? Rabba said to him in response: It is prohibited.

Rav Huna said: In the case of two courtyards, it is prohibited to carry, even if the residents of the two courtyards made an eiruv together. This is because of a decree lest they come to say that an eiruv is effective for the area between the upright boards. Rava, however, disagreed and said: If they made an eiruv together, it is permitted to carry between the courtyards and the area between the boards, and vice versa; with the preparation of the eiruv, the two courtyards are regarded as one.

Abaye said to Rava: What was taught in a baraita supports your opinion, for the baraita states: In the case of a courtyard, one end of which interposes between the upright boards surrounding a well, it is permitted to carry from inside the courtyard to the area between the upright boards, and from the area between the upright boards into the courtyard, but if there were two adjacent courtyards, this is prohibited. With regard to which case was this statement made? The statement applies where the residents of the two courtyards did not make an eiruv together; but if they made an eiruv together, it is permitted to carry between the courtyards and the area between the boards, and vice versa.

The Gemara asks: Shall we say that this is a refutation of the opinion of Rav Huna, for the baraita explicitly contradicts his opinion? The Gemara rejects this argument: Rav Huna could have said to you: There, the baraita is dealing with a case where the two courtyards later became joined by means of the wall that separated them being breached, and it is clear to all that it is a single courtyard, so that there is no concern that people will say that an eiruv is effective for the area between the boards.

Abaye asked Rabba yet another question: If the water in the cistern dried up on Shabbat, what is the law? Is it still permitted to carry between the boards? Rabba said to him: The boards are considered a valid partition only on account of the water; since there is no longer any water here, there is also no longer a valid partition here.

Ravin raised a dilemma: If the water in the well dried up on Shabbat, and then on the same Shabbat it rained and other water came in its place, what is the law? Is the original allowance to carry restored? Abaye said to him: The case where the water dried up on Shabbat should not be a dilemma for you, for I already raised this dilemma before my Master, Rabba, and he resolved for me that it is prohibited to carry in the enclosed area.

The case where other water came on Shabbat should also not be a dilemma for you, for this is a case of a partition erected on Shabbat, and it was already taught in a baraita: Any partition erected on Shabbat, whether it was erected unwittingly, or whether intentionally, whether by unavoidable accident, or whether willingly, it is called a valid partition. The fact that it was erected in a prohibited manner, in violation of prohibitions related to building, does not negate its effectiveness.

Ravin raised a difficulty: Was it not stated with regard to this halakha that Rav Naḥman said: They only taught that such a partition is called a partition as a stringency; it is prohibited by Torah law to throw objects from an area enclosed by such a partition into the public domain and vice versa, but to carry in it as a full-fledged private domain is not permitted by the Sages?

The Gemara refutes this objection: Rav Naḥman’s statement applies only in a case where the partition was erected intentionally. Since the partition was erected intentionally on Shabbat, the Sages imposed a penalty that it is prohibited to carry within the enclosed area. However, in the case of a partition that was erected unwittingly or that arose by itself, no such penalty was imposed, and it is permitted to carry there.

Rabbi Elazar said: One who throws an object from the public domain into the area between the upright boards surrounding a well is liable. The Gemara asks: This is obvious, for were it not a valid partition, how could he be permitted to draw water from the well? This shows that it is a full-fledged private domain.

The Gemara answers: Rabbi Elazar’s ruling is only necessary to teach that in the case where one arrange an enclosure similar to the upright boards surrounding a well in the public domain, in a place where there was no well, and threw an object into it from the public domain, he is liable.

The Gemara raises a difficulty: Isn’t this obvious as well? As, were it not regarded as a partition in general, how could he be permitted to carry in the case of a cistern? The Gemara explains: It is only necessary to teach you that even though such a partition does not bar entry and many people pass through it, it is nonetheless considered a partition in regard to Shabbat.

The Gemara asks: And what is he teaching us by this statement, that the passage of many people does not come and negate the effectiveness of a partition? But Rabbi Elazar stated this idea once before.

As we learned in a mishna: Rabbi Yehuda says the following with regard to the upright boards surrounding a well: If the path of the public domain passes through the area of the wells and the posts and obstructs them, he must divert it to the sides, or else the partition is invalid. And the Rabbis say: He need not divert the path of the public domain, for even if many people pass through there, the partition is valid. With regard to this mishna, Rabbi Yoḥanan and Rabbi Elazar both said: Here, the Rabbis informed you of the strength of partitions. Therefore, we see that Rabbi Elazar already expressed his opinion that the validity of a partition is not canceled by the passage of many people through it.

The Gemara answers: If it was derived from there alone, I would have said that what Rabbi Elazar meant is that here the Rabbis informed you of the strength of partitions, but he, Rabbi Elazar, does not agree with them. He therefore teaches us in his present ruling that what he meant is that here they informed you of this law and he agrees with them.

The Gemara asks: If so, let Rabbi Elazar say this ruling that one who throws an object into the area enclosed by upright boards is liable, and he would not have need to make his other comment that here the Rabbis informed you of the strength of partitions. The Gemara answers: Rabbi Elazar did not in fact make two statements, but rather one was stated by inference from the other. He only made one of these statements explicitly; the other was reported by his students in his name based on an inference from what he had said.

We learned in the mishna: It is permitted to bring the upright boards closer to the well, provided that the enclosed area is large enough for a cow to stand in and drink, with its head and most of its body inside the partitioned space. Similarly, we learned there in a mishna: A person may not stand in a public domain and drink in the private domain, and likewise he may not stand in the private domain and drink in a public domain, unless he brings his head and most of his body into the place where he is drinking.

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Eruvin 20a examines carrying laws between courtyards and the space enclosed by boards around a well, weighing whether a shared eruv permits joint use.