Joshua 6:2-5

2And the Lord said to Joshua, "See, I have given Jericho into your hand, with its king and mighty men of valor.

3You shall march around the city, all the men of war going around the city once. Thus shall you do for six days.

4Seven priests shall bear seven trumpets of rams' horns before the ark. On the seventh day you shall march around the city seven times, and the priests shall blow the trumpets.

5And when they make a long blast with the ram's horn, when you hear the sound of the trumpet, then all the people shall shout with a great shout, and the wall of the city will fall down flat, and the people shall go up, everyone straight before him."