Joshua 6:4, 8-9

Also seven priests shall carry seven trumpets of rams’ horns before the ark; then on the seventh day you shall march around the city seven times, and the priests shall blow the trumpets.

And it was so, that when Joshua had spoken to the people, the seven priests carrying the seven trumpets of rams’ horns before the LORD went forward and blew the trumpets; and the ark of the covenant of the LORD followed them. The armed men went before the priests who blew the trumpets, and the rear guard came after the ark, while they continued to blow the trumpets.