LOOK UP in the Sky… The First Mitzvah!
The special Mitzvah of establishing the exact day of Rosh Chodesh is known as Kiddush HaChodesh. In fact, it was the very first Mitzvah given to Bnei Yisrael as a nation.
Here’s how it works:
The moon goes through phases every month. At first, at the beginning of each month, it looks like a tiny sliver. It then “grows” and “grows” until it becomes a “full moon” in the middle of the month. And gradually it “shrinks” until it completely disappears at the end of the month. This cycle repeats itself every single month.
Long ago, in the land of Israel, Jews would look up to the sky at the beginning of each month and search for the “new moon,” so they could perform the Mitzvah of Kiddush HaChodesh.
If a pair of witnesses would see the “new moon” they would quickly travel to Jerusalem. There they would testify before the “Supreme Jewish Court” called the Sanhedrin.
All witnesses were questioned in order of their arrival. The elder of the first pair was asked many questions, such as:
- What was the moon’s position, relative to the sun?
- What was the position of the moon’s dark side, relative to the sun?
- How wide was the moon?
- How high in the sky did the moon appear?
After questioning the first witness, his partner was brought in and cross-examined. If the two testimonies matched, they were accepted and everyone would call out, “Mekudash, Mekudash! Today is the holy day of Rosh Chodesh, the first day of the month!”
BTW: All remaining pairs of witnesses were questioned too, even though their testimonies were no longer needed. This was so that they would not feel discouraged from coming again in the future.
Knowing the exact day of Rosh Chodesh is of supreme importance because this determines the exact date of our Jewish holidays. For example, Passover is on the 15th day of Nissan – so we need to count 15 days from Rosh Chodesh in order to celebrate the holiday on the proper day.