Joshua 6:4-7

Have seven priests carry shofars in front of the ark. On the seventh day, march around the city seven times, with the priests blowing the shofars. When you hear the blare of the shofars, have all the people shout with a mighty shout of joy! Then the walls of the city will collapse before your eyes, and your whole army must charge straight in!” So Joshua son of Nun summoned the priests and instructed them: “Take up the ark of the covenant, and have seven priests carry seven shofars in front of the ark of YAHWEH.” And to the people he said, “Forward! March around the city and set an advance guard of armed men to march ahead of the ark of YAHWEH.”