The commandment to proclaim the New Moon was the first commandment given to the entire Jewish nation. In Exodus 12, God says: This month shall mark for you the beginning of the months – it shall be the first of the months of the year for you” When Israel was enslaved in Egypt, they were not in control of their time. Upon freeing them, the Almighty put the setting of the calendar in their hands.
The Hebrew calendar is essentially lunar, and the lunar year has 354 days. The solar year is 365 days. In order to ensure that the Biblical holidays remain in their proper seasons, the calendar is adjusted by adding a 13th month to the calendar about every 3 years. The Jewish people are likened to the moon. The moon has no light of its own – it receives everything from the sun. Israel is totally dependent on the Creator for its very existence and the blessings they receive.
In addition, the moon waxes and wanes. After reaching its fulness, the moon diminishes in size until it can no longer be seen. One could assume that it is no longer in existence. But then the moon renews and its brightness grows steadily.
The moon illuminates the world during the darkness of night time and God established Israel to be a light to the nations, as Isaiah the prophet repeats in 42:6 and 49:6. Isaiah tells us in chapter 60:1-3 that one day, the nations of the world will come to Israel’s light.
This video explores various paths to understanding the significance of the month of Kislev.