Then all the troops who were with him marched up and approached the city. They arrived in front of Ai and camped to the north of it, with the valley between them and the city.
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 all the people, even the people of war that were with him, and went up, and drew nigh,.... To the city of Ai: and came before the city; as if they intended to besiege it, storm it, or force an entrance into it: and pitched on the north side of Ai; which was judged fittest for the purpose: now there was a valley between...
there was a valley between them and Ai--literally, "the valley."