Joshua 6:8, 13

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 seven priests bearing seven trumpets of rams' horns before the ark of the LORD went on continually, and blew with the trumpets: and the armed men went before them; but the rereward came after the ark of the LORD, the priests going on, and blowing with the trumpets.