Siman 378

Three courtyards that open into one another, and all of them also open to the public domain or to a mavoi, in a manner where they are not forced to pass specifically through the preceding courtyard—for in such a case it would be called "one inside the other" and there are other laws concerning them, as will be explained—if all three of them made an eruv together, they are all permitted to one another, even with vessels that were in the houses at the onset of Shabbat. And if they did not make an eruv with one another at all, but rather each one made an eruv for itself or they did not make an eruv at all, it is forbidden to carry from this courtyard to that courtyard vessels that were in the house at the onset of Shabbat. And if two made an eruv and one did not make an eruv with them, the two are permitted and the one is forbidden, and they are also forbidden to its courtyard with vessels that were in the house at the onset of Shabbat.

However, if the middle one made an eruv with each of the outer ones, for a person has the right to dwell in two places, as I have written in siman 372, section 15, see there, but the outer ones did not make an eruv with one another—it follows that the outer ones are forbidden to one another to take out vessels that rested in the houses from one to the other via the middle one, but the middle one is permitted with each of them and they are permitted with it. And we are not concerned that since many vessels of this one and that one are frequently in the middle one, the owners of the outer ones will forget and one will take out the vessels of its fellow into its own courtyard—we are not concerned for this, just as we are not concerned above in siman 349 regarding three people where each has four amot, and the area of the middle one is swallowed between them—that we are not concerned lest the outer one carry into his own area the vessels of the second outer one, and here too it is so. (Gemara 48a, according to Rabbi Shimon, for the halacha is like him)

In what case are these matters stated? When the middle one placed its eruv in this one and its eruv in that one, for then the middle one has two dwellings in the two outer ones, but the outer ones do not have dwellings in the middle one, since they did not place their eruv in the middle one. And also, even if they placed their eruv in the middle one, but they placed it in two houses, it follows that the outer ones have no connection to one another, for this one dwells in this house and that one in another house. But if both of them placed it in one house in the middle one—behold they are all joined, and all three are permitted with one another, such as if they all placed it in one vessel, or if it did not fit in one vessel and they placed them in two vessels. And according to what we explained above in siman 367, section 11, that without meticulousness we are not concerned at all regarding two vessels—it follows well with simplicity. (And so implies the plain meaning of the sugya on 41a: which mentioned only two houses, see there.)

And ostensibly, when the two outer ones placed their eruv in the middle one in two houses, and it is as if they all dwell in the middle one, if so, the eruv should be completely nullified, since they divided the eruv into two houses, and it is like a courtyard where some of them made an eruv for themselves and some for themselves—who forbid one another. However, concerning this they replied in the Gemara (ibid.): "If they said 'dwellers' to be lenient, shall they say 'dwellers' to be stringent?" That is to say, certainly one or two of the residents of the courtyard who did not give a portion in the eruv—forbid the residents of the courtyard. But here, behold the outer ones do not actually dwell here, rather the eruv brought them into its midst, and we do not make them like actual dwellers to be stringent upon the residents of the courtyard and nullify their eruv. But it is not a general rule, for sometimes we say even to be stringent, where she was negligent herself, as will be explained regarding two courtyards, one inside the other. (When one from the inner one forgot and did not make an eruv, that the outer one forbids it because of the eruv; so wrote the Tosafot there s.v. 'yamru', see there)

Two courtyards, one inside the other, where the outer one is open to an alleyway or to the public domain, and the inner one is open to the outer one and not to the alleyway or to the public domain, and through this it necessarily has the right of passage over the outer one, for it has no other path; and it has already been explained that a foot permitted in its own place does not prohibit in a place other than its own, and a foot prohibited in its own place prohibits in a place other than its own, as I wrote in siman 375 regarding the residents of the courtyard and the residents of the balcony. Therefore, even if these two courtyards did not make an eruv together, but rather each one for itself—nevertheless, the inner one does not prohibit by its right of passage over the outer one, since it is permitted in its own place. But if the inner one did not make an eruv for itself, or if it did make an eruv and one of the residents of the courtyard forgot and did not make the eruv, such that the eruv is void—it prohibits the outer one, because it is a foot prohibited in its own place. But the outer one over the inner one—it can never prohibit, since it does not have the right of passage over the inner one. Therefore, if the inner one made an eruv for itself and the outer one did not make an eruv, or if it did make an eruv and one of the residents of its courtyard forgot and did not make the eruv—the inner one is permitted and the outer one is prohibited. And one should not ask why we said regarding one who forgot from the inner one that it prohibits the outer one because the inner one is prohibited in its own place, for it could be permitted in its own place by having the one who forgot to make the eruv nullify his domain to them, as will be explained in siman 380. For it can be said that certainly it is so, and if he nullifies the domain to them—the outer residents will return to their fitness, and it appears that they can even compel him to nullify.

If these two courtyard areas made an eruv together and placed their eruv in the outer one, and one person—whether from the inner one or the outer one—forgot and did not join the eruv, both are forbidden until he nullifies his domain. For even if the negligence was from the outer one, nevertheless, the inner one cannot close itself off, since its eruv is not with it. And the outer one is automatically forbidden, even if the negligence was from the inner one, since the inner one has the right of passage over it, and it is forbidden in its own place. But if they placed the eruv in the inner one, if one person from the outer one forgot and did not join the eruv, the inner one closes its entrance and does not allow the residents of the outer one to come to it. Even though through the eruv they became as one courtyard, it is because it can say, "I joined with you for my benefit and not for my detriment," and since the negligence is from you, you have no connection to me. But if one person from the inner one did not join the eruv, both are forbidden until he nullifies the domain. For since the inner one is forbidden, it perforce forbids the outer one which has the right of passage over it. And if this resident of the inner one who did not join the eruv wishes to nullify his domain only to the inner one and not to the outer one, it is not in his power; for if so, the residents of the outer one would forbid them, as the eruv makes it as if it has the right of passage, since the detriment is from the inner resident, as I wrote at the end of section 4. (And according to this, for the one who holds in the Gemara "there is no nullification of domain from courtyard to courtyard," both remain in their state of prohibition; however, we hold "there is nullification of domain from courtyard to courtyard," as I wrote in siman 381, and therefore in such a case he should be careful to nullify his domain to the residents of both courtyards.) (From Rashi 60. and 83: it is explained that in one courtyard even a permitted foot forbids, see there.)

If an individual who does not require an eruv dwells in the inner one and an individual in the outer one, or two in the outer one and they made an eruv—the inner individual does not prohibit them, for he is a foot that is permitted in its own place. And likewise if many who are like an individual dwell in the inner one, who do not need to make an eruv between them, such as a father and his son or a teacher and his student who receive support, as was written in siman 370; and likewise three courtyards one inside the other and an individual in each one, even though the two inner ones pass through the outer one—nevertheless they do not prohibit it, because each one is a foot that is permitted in its own place. And if there were two in the third inner one and they did not make an eruv—they prohibit the middle one and the outer one, since they are prohibited in their own place. And if there are two in the middle one and they did not make an eruv—they prohibit the outer one, and so too anything similar to this.