He impaled the body of the king of Ai on a pole and left it there until evening. At sunset, Joshua ordered them to take the body from the pole and throw it down at the entrance of the city gate. And they raised a large pile of rocks over it, which remains to this day.
John Calvin
Though he seems to have treated the king with great severity in order to satisfy the hatred of the people, I cannot doubt that he studied faithfully to execute the divine judgment. Conquerors, indeed, are wont to spare captive kings, because their rank seems to carry something venerable along with it, but the condition of kings was different among those nations in which God wished particularly to show how greatly he detested the wickedness which he had so long tolerated. For while all were doomed to destruction, the divine vengeance justly displayed itself with greater sternness and severity on the leaders, with whom the cause of destruction originated.
We may add, that the ignominious punishment inflicted on the king rendered it still less necessary to deal leniently with the common people, and thus prevented the Israelites from indulging an unseasonable mercy, which might have made them more sluggish or careless in executing the work of universal extermination.
God purposely delivered the king alive into the hand of Joshua, that his punishment might be more marked and thus better adapted for an example. Had he fallen in the conflict promiscuously with others, he would have been exempted from this special mark of infamy; but now even after his death, the divine vengeance pursues his corpse. Nay, after being hung, he is thrown forth at the gate of the city where he had sat on his throne in judgment, and a monument is erected for the purpose of perpetuating his ignominy to posterity. His burial, however, is mentioned to let us know that nothing was done through tumultuous impetuosity, as Joshua carefully observed what Moses had prescribed in the Law, (Dt 21:23) namely, that those hung on gibbets should be taken down before sunset, as a spectacle of the kind was held in abomination. And, certainly, while it is humane to bury the dead under ground, it is inhumanly cruel to cast them forth to be torn by wild beasts or birds. Therefore, that the people might not be accustomed to barbarity, God allowed criminals to be hung, provided they did not hang unburied for more than one day. And that the people might be more attentive to this duty, which otherwise might readily have been neglected, Moses declares that every one who hangs on a tree is accursed; as if he had said, that the earth is contaminated by that kind of death, if the offensive object be not immediately taken away.
