Joshua 6:8 (KJV)

And Joshua the son of Nun called the priests, and said unto them, Take up the ark of the covenant, and let seven priests bear seven trumpets of rams’ horns before the ark of the Lord.

And he said unto the people, Pass on, and compass the city, and let him that is armed pass on before the ark of the Lord.

And it came to pass, when Joshua had spoken unto the people, that the seven priests bearing the seven trumpets of rams’ horns passed on before the Lord, and blew with the trumpets: and the ark of the covenant of the Lord followed them.

And the armed men went before the priests that blew with the trumpets, and the rereward came after the ark, the priests going on, and blowing with the trumpets.

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.