New Moon dilemmas
החדש הזה לכם ראש חדשים ראשון הוא לכם לחדשי השנה
This month shall be for you the beginning of the months. It is the first for you for the months of the year
Our Sages learn from this verse the mitzvah of Sanctifying the New Moon. Unlike our current calendar, which is fixed, the Jewish months originally weren’t set in stone. For the new month to begin, two witnesses had to declare in a Jewish Court that they had seen the Moon after the New Moon occurred. Three judges would interrogate the witnesses, and after confirming that they weren’t mistaken, the judges would declare the month sanctified, and the new month would begin.