Cross reference
Joshua 6:8
8 So after Joshua had said this to the people, the seven priests with their seven horns went forward before the Lord, blowing on their horns: and the ark of the Lord's agreement went after them.
Numbers 32:20
20 Then Moses said to them, If you will do this, arming yourselves to go before the Lord to the war,
Joshua 6:3-4
3 Now let all your fighting-men make a circle round the town, going all round it once. Do this for six days.
4 And let seven priests go before the ark with seven loud-sounding horns in their hands: on the seventh day you are to go round the town seven times, the priests blowing their horns.