Numbers 10:10-11

10And in the day of your gladness, and in your set feasts, and in your new moons, ye shall blow with the trumpets over your burnt-offerings and over your sacrifices of peace-offering; and they shall be to you for a memorial before your 1God: I am Jehovah your 2God.

11And it came to pass in the second year, in the second month, on the twentieth of the month, that the cloud was taken up from off the tabernacle of the testimony.