A person may attach a condition to his eruv and say, ‘‘If gentiles come from the east, my eruv is to the west; if from the west, my eruv is to the east; if they come from both directions, I shall go to the place I choose; if they do not come from either direc-tion, I am as my townspeople.’’ ‘‘If a scholar comes from the east, my eruv is to the east; from the west, my eruv is to the west; if one comes to here and [one comes] to there, I shall go to the place I choose; if to neither direction, I am as my townspeople.’’ R’ Yehudah says: If one of the scholars was his teacher, he must go to his teacher. But if both were his teachers, he may go to the place he chooses.

R’ Eliezer says: If Yom Tov adjoins the Sabbath either before it or after it — a person may make two eruvin and declare, ‘‘My eruv [for] the first is to the east and [for] the second to the west’‘; ‘‘[for] the first to the west and [for] the second to the east’’; ‘‘My eruv is [for] the first, but [for] the second I am as my townspeople’’; [or] ‘‘My eruv is [for] the second, but [for] the first I am as my townspeople.’’ But the Sages say: He makes an eruv to one direction or he makes no eruv at all; either he makes an eruv for both days or he makes no eruv at all. How should one proceed? He should take it on the first and stay with it until nightfall, then take it and go. On the second, he should stay with it until nightfall, then eat it. Thus he benefits in his walking [area], and he benefits from his eruv. If it was eaten on the first the eruv is valid for the first, but the eruv is not valid for the second. Said R’ Eliezer: [So] you agree with me that they are two [periods of] holiness!