'New Moon' in the Bible

David said to Jonathan, “Behold, tomorrow is the New Moon [observance], and I should sit at the table to eat [the sacrificial meal] with the king; but let me go, so that I may hide myself in the field until the third evening.

Then Jonathan said to David, “Tomorrow is the New Moon [festival], and you will be missed because your seat will be empty.

So David hid in the field; and when the New Moon [festival] came, the king sat down to eat food.

But on the next day, the second day of the new moon, David’s place was empty [again]; and Saul said to Jonathan his son, “Why has the son of Jesse not come to the meal, either yesterday or today?”