God had given Joshua specific instructions that included having the priests march around the walled city of Jericho seven times. They obeyed and the walls came down.
1 Now Jericho was shut up inside and outside because of the people of Israel. None went out, and none came in.2 And the LORD said to Joshua, “See, I have given Jericho into your hand, with its king and mighty men of valor.3 You shall march around the city, all the men of war going around the city once. Thus shall you do for six days.4 Seven 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.5 And 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.”6 So Joshua the son of Nun called the priests and said to them, “Take up the ark of the covenant and let seven priests bear seven trumpets of rams' horns before the ark of the LORD.”7 And he said to the people, “Go forward. March around the city and let the armed men pass on before the ark of the LORD.”8 And just as Joshua had commanded the people, the seven priests bearing the seven trumpets of rams' horns before the LORD went forward, blowing the trumpets, with the ark of the covenant of the LORD following them.9 The armed men were walking before the priests who were blowing the trumpets, and the rear guard was walking after the ark, while the trumpets blew continually.
