The head of the beis din says, “It is sanctified!”  And all the people respond after him, “It is sanctified! It is sanctified!”  Whether it appeared at its [expected] time or whether it did not appear at its [expected] time, they sanctify [the day].  R’ Elazar bar Tzadok says: If it did not appear at its [expected] time, they do not sanctify, for it has already been sanctified by Heaven.

Rabban Gamliel had moon-shaped forms on a tablet and on the wall of his upper chamber, which he would show the simple folk, and say [to them], “Did you see [the moon] like this or like that?”  It happened that two [witnesses] came and said, “We saw it in the morning in the east and in the evening in the west.” R’ Yochanan ben Nuri said, “They are false witnesses!” [But] when they came to Yavneh, Rabban Gamliel accepted them.  On another occasion two [witnesses] came and said, “We saw it at its [expected] time,” but on the night of the added day it did not appear; and Rabban Gamliel accepted them.  R’ Dosa ben Harkinas said, “They are false witnesses. How can they testify that a woman gave birth and the next day her belly is between her teeth?”  R’ Yehoshua said to him, “I agree with your argument.”