Numbers 10:10-11

10Also 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.

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