Rosh Hashana 2:7-8

Rosh Hashana 2:7

The head of the court declared the new month consecrated and everyone answered after him, “Consecrated, consecrated.” The new month was consecrated whether the moon was seen at the designated time (i.e., on the eve of the 30^th day) or not. Rabbi Eliezer bar Tzadok said that if the moon was not seen at the designated time, the month was not consecrated because it was already consecrated automatically by Heaven.

Rosh Hashana 2:8

Rabban Gamliel had charts depicting the various phases of the moon, which he would show to unlearned witnesses. He would ask them, “Did it look like this, or like this?” It once happened that two witnesses came claiming that they had seen the moon in the east in the morning and in the west in the evening. Rabbi Yochanan ben Nuri said that they were false witnesses but when they came to Yavne, Rabban Gamliel accepted their testimony. On another occasion, two witnesses came claiming that they had seen the moon in its designated time (on the eve of the 30^th day) but then it was not seen on the evening of intercalation (i.e., the eve of the 31^st day). Rabban Gamliel accepted their testimony but Rabbi Dosa ben Harkinus said that they were false witnesses. He likened their testimony to a person claiming that on one day a certain woman had given birth and on the next day she was still pregnant. Rabbi Yehoshua agreed that Rabbi Dosa’s opinion made sense.