Bible Verses About Months: Commenced with first appearance of new moon

Also in the day of your gladness, and in your set feasts, and in the beginnings of your months, ye shall blow the trumpets over your burnt-offerings, and over the sacrifices of your peace-offerings; and they shall be to you for a memorial before your God: I am Jehovah your God.

Blow the trumpet at the new moon, At the full moon, on our feast-day.