Numbers 10:9-11

Modern English Version

⁹ And if you go to war in your land against the enemy that oppresses you, then you will blow an alarm with the trumpets, and you will be remembered before the Lord your God, and you will be saved from your enemies. ¹⁰ Also in the day of your gladness, and at your appointed days, and in the beginnings of your months, you shall blow the trumpets over your burnt offerings, and over the sacrifices of your peace offerings that they may be a memorial for you before your God. I am the Lord your God.

The Departure From Sinai

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