Joshua 6:8-10

8After Joshua had spoken to the people, seven priests carrying seven rams’ horns before the LORD advanced and blew the horns, and the ark of the covenant of the LORD followed them. 9While the horns continued to sound, the armed troops marched ahead of the priests who blew the horns, and the rear guard followed the ark.

10But Joshua had commanded the people: “Do not give a battle cry or let your voice be heard; do not let one word come out of your mouth until the day I tell you to shout. Then you are to shout!”