20 Then the men of Ai, looking back, saw the smoke of the town going up to heaven, and were unable to go this way or that: and the people who had gone in flight to the waste land were turned back on those who were coming after them.

Matthew Henry's Commentary on Joshua 8:20

Commentary on Joshua 8:3-22

(Read Joshua 8:3-22)

Observe Joshua's conduct and prudence. Those that would maintain their spiritual conflicts must not love their ease. Probably he went into the valley alone, to pray to God for a blessing, and he did not seek in vain. He never drew back till the work was done. Those that have stretched out their hands against their spiritual enemies, must never draw them back.