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

[47] And with these words did Moses encourage the multitude, who then called together the princes of their tribes, and their chief men, both separately and conjointly. The young men he charged to obey their elders, and the elders to hearken to their leader. So the people were elevated in their minds, and ready to try their fortune in battle, and hoped to be thereby at length delivered from all their miseries: nay, they desired that Moses would immediately lead them against their enemies without the least delay, that no backwardness might be a hindrance to their present resolution. So Moses sorted all that were fit for war into different troops, and set Joshua, the son of Nun, of the tribe of Ephraim, over them; one that was of great courage, and patient to undergo labors; of great abilities to understand, and to speak what was proper; and very serious in the worship of God; and indeed made like another Moses, a teacher of piety towards God. He also appointed a small party of the armed men to be near the water, and to take care of the children, and the women, and of the entire camp. So that whole night they prepared themselves for the battle; they took their weapons, if any of them had such as were well made, and attended to their commanders as ready to rush forth to the battle as soon as Moses should give the word of command. Moses also kept awake, teaching Joshua after what manner he should order his camp. But when the day began, Moses called for Joshua again, and exhorted him to approve himself in deeds such a one as a his reputation made men expect from him; and to gain glory by the present expedition, in the opinion of those under him, for his exploits in this battle. He also gave a particular exhortation to the principal men of the Hebrews, and encouraged the whole army as it stood armed before him. And when he had thus animated the army, both by his words and works, and prepared every thing, he retired to a mountain, and committed the army to God and to Joshua.