Commentaries
8:23-29 God, the righteous Judge, had sentenced the Canaanites for their wickedness; the Israelites only executed his doom. None of their conduct can be drawn into an example for others. Especial reason no doubt there was for this severity to the king of Ai; it is likely he had been notoriously wicked and vile, and a blasphemer of the God of Israel.
23. the king of Ai they took alive, and brought him to Joshua—to be reserved for a more ignominious death, as a greater criminal in God's sight than his subjects. In the mingled attack from before and behind, all the men were massacred.