Josh 6:4-5

4with seven priests bearing seven trumpets of rams' horns before the ark. On the seventh day you shall march around the city seven times, the priests blowing the trumpets.5When they make a long blast with the ram's horn, as soon as you hear the sound of the trumpet, then all the people shall shout with a great shout; and the wall of the city will fall down flat, and all the people shall charge straight ahead.”