Numbers 10:7-9

Contemporary English Version

⁷ But when you want everyone to come together, sound a different signal on the trumpet. ⁸ The priests of Aaron's family will be the ones to blow the trumpets, and this law will never change.

⁹ Whenever you go into battle against an enemy attacking your land, give a warning signal on the trumpets. Then I, the Lord, will hear it and rescue you.