Joshua got up early the next morning and mobilized his men, and he and the elders of Israel marched before them up to Ai.
We have here an account of the taking of Ai by stratagem. The stratagem here used, we are sure, was lawful and good; God himself appointed it, and we have no reason to think but that the like is lawful and good in other wars.
Commenting on Joshua 8:3-22
And Joshua rose up early in the morning, and numbered the people,.... To see if there were any wanting, and to put them in proper order for their march: and went up, he and the elders of Israel, before the people to Ai; these elders were either the seventy elders who went with Joshua as council to him; or it may be rather they were...
Joshua . . . numbered the people--that is, the detachment of liers-in-wait; he did this, to be furnished with clear evidence afterwards, that the work had been done without any loss of men, whereby the people's confidence in God would be strengthened and encouragement given them to prosecute the war of invasion with vigor.