'New moon' in the Bible

And David said unto Jonathan, Behold, tomorrow is the new moon, and I should not fail to sit with the king to eat: but let me go, that I may hide myself in the field unto the third day at evening.

Then Jonathan said to David, Tomorrow is the new moon: and you shall be missed, because your seat will be empty.

So David hid himself in the field: and when the new moon was come, the king sat himself down to eat the feast.