Joshua 6:4

And seven priests shall bear before the ark, which was thus conspicuous in the line of march, seven trumpets of rams' horns, very large instruments, with a deep-toned, terrifying sound, especially when the notes were sustained; and the seventh day ye shall compass the city seven times, and the priests shall blow with the trumpets. The repetition on the several days of this procession about the city could only be intended to exercise Israel in unconditional faith and patient trust in the power and help of God, and to impress deeply upon the people the fact that it was the almighty power and faithfulness of Jehovah alone which gave into their hands this fortified city, one of the strongest in the land. The last day was surely the strongest test of their faith, for the besieged were probably not sparing in their jeering cries of contempt for a great host that ventured no attack, but continued on its endless procession around the city.