Charles Ellicott Commentary Joshua 8:14

"And it came to pass, when the king of Ai saw it, that they hasted and rose up early, and the men of the city went out against Israel to battle, he and all his people, at the time appointed, before the Arabah; but he knew not that there was an ambush against him behind the city." — Joshua 8:14 (ASV)

When the king of Ai saw it... the city went out.—The stratagem succeeded perfectly. Joshua gave them ample time, by his movements in open daylight, to discover what his apparent intentions were, namely, to renew the direct attack upon the city with a larger force.

Accordingly, the Canaanites came out before the plain—that is, in the direction of the plain of Jordan (the Arabah. On this word and Emek and Gai used above, see Stanley, Sinai and Palestine)—intending to drive Joshua down by the way he had come up. And accordingly Joshua and his army fled in that very direction by the way of the Midbar or wilderness—that is, the mountainous district between Ai and the Jordan valley, and lying in that direction. (Compare to Joshua 7:5.)