Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[22] Now while the Israelites did this, and the Canaanites did not attack them, but kept themselves quiet within their own walls, Joshua resolved to besiege them; so on the first day of the feast [of the passover], the priests carried the ark round about, with some part of the armed men to be a guard to it. These priests went forward, blowing with their seven trumpets; and exhorted the army to be of good courage, and went round about the city, with the senate following them; and when the priests had only blown with the trumpets, for they did nothing more at all, they returned to the camp. And when they had done this for six days, on the seventh Joshua gathered the armed men and all the people together, and told them these good tidings, That the city should now be taken, since God would on that day give it them, by the falling down of the walls, and this of their own accord, and without their labor. However, he charged them to kill every one they should take, and not to abstain from the slaughter of their enemies, either for weariness or for pity, and not to fall on the spoil, and be thereby diverted from pursuing their enemies as they ran away; but to destroy all the animals, and to take nothing for their own peculiar advantage. He commanded them also to bring together all the silver and gold, that it might be set apart as first-fruits unto God out of this glorious exploit, as having gotten them from the city they first took; only that they should save Rahab and her kindred alive, because of the oath which the spies had sworn to her.