Numbers 10:10-11

¹⁰And on days of joy and on your regular feasts and on the first day of every month, let the horns be sounded over your burned offerings and your peace-offerings; and they will put the Lord in mind of you: I am the Lord your God.

¹¹Now in the second year, on the twentieth day of the second month, the cloud was taken up from over the Tent of witness.