Study Eruvin folio 38A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
don’t you at least concede that we must be concerned that perhaps the leather flask will burst, and retroactively this person would have been drinking tevel? R' Meir said to them: When it bursts, I will consider the matter, but now I am not concerned about this possibility.
Mishnah: R' Eliezer says: With regard to a Festival adjacent to Shabbat, whether before it, on a Friday, or after it, on a Sunday, a person may establish two eiruvin of Shabbat borders [teḥumin] and say as follows: My eiruv on the first day shall be to the east, and on the second day to the west
And the Rabbis disagree and say that such a split is impossible. Rather, he either establishes an eiruv in one direction for both days, or he establishes no eiruv at all; either he establishes an eiruv for the two days, or he establishes no eiruv at all.
What does one do to establish an eiruv that will be valid for both the Festival and Shabbat? He or his agent brings the eiruv to the location that he wishes to establish as his residence on the eve of the first day, and he stays there with it until nightfall, the time when the eiruv establishes tha
However, if the eiruv was eaten on the first day, his eiruv is effective for the first day, and his eiruv is not effective for the second day.