Joshua 6:4-7

Also seven priests shall carry seven trumpets of rams’ horns before the ark; then on the seventh day you shall march around the city seven times, and the priests shall blow the trumpets. It shall be that when they make a long blast with the ram’s horn, and when you hear the sound of the trumpet, all the people shall shout with a great shout; and the wall of the city will fall down flat, and the people will go up every man straight ahead.” So Joshua the son of Nun called the priests and said to them, “Take up the ark of the covenant, and let seven priests carry seven trumpets of rams’ horns before the ark of the LORD.” Then he said to the people, “Go forward, and march around the city, and let the armed men go on before the ark of the LORD.”