Numbers 10:10-11

¹⁰And on the day of your gladness, and on your appointed festivals, and on the beginnings of your months, shall ye blow with 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 the Lord 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 off the tabernacle of the testimony.