Numbers 10:9-10

“When you arrive in your own land and go to war against your enemies who attack you, sound the alarm with the trumpets. Then the LORD your God will remember you and rescue you from your enemies. Blow the trumpets in times of gladness, too, sounding them at your annual festivals and at the beginning of each month. And blow the trumpets over your burnt offerings and peace offerings. The trumpets will remind your God of his covenant with you. I am the LORD your God.”