The destruction of the city—and the curse Joshua pronounces—are pretty harsh things. Today, of course, there are rules of war, and the international community would punish this kind of military action. But that wasn’t the situation in Canaan. The Israelites are invaders in the land, badly outnumbered, and their victory and decisive actions send a message to all the other cities and towns: there’s something different—and very dangerous—about these invaders. Moreover, it is essential to purify the land of polytheistic worship before Israel settles in the land with their worship of the Lord.