Joshua 6:10

But 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!”

And Joshua had commanded the people, saying, Ye shall not shout, nor make any noise with your voice, neither shall any word proceed out of your mouth, until the day I bid you shout; then shall ye shout.