Put yourself in Joshua's shoes as you hear these battle plans:
March around the city once with all the armed men. Do this for six days. Have seven priests carry trumpets of rams' horns in front of the ark. On the seventh day, march around the city seven times, with the priests blowing the trumpets. When you hear them sound a long blast on the trumpets, have all the people give a loud shout; then the wall of the city will collapse and the people will go up, every man straight in.
Let's be honest. That's weird. If you're Joshua, you're wanting a second opinion at this point. Why did God design this battle plan for taking the first city in the Promised Land? Don't miss what God was doing. He was divinely orchestrating the events of his people so that in the end only he could get the glory for what would happen. Read the rest of Joshua 6, and you will see them take the city of Jericho just as God has outlined. But notice carefully what you don't see. You don't see all the Israelites going up to the trumpet players and telling them what an incredible job they did that day. I can almost hear them now: "Abishai, I've never heard you play that well." "Nimrod, when you hit the high C, that was beautiful, man." No. Instead you see the people of Israel realising that only God could have done this.
This is how God works. He puts his people in positions where they are desperate for his power, and then he shows his provision in ways that display his greatness.