The purpose of the conquest was to drive the tribes out of the land to occupy it. Some allowance probably needs to be made for the cultural aspect of exaggeration used at the time for war stories. We sometimes have a coach tell his team to go out and kill the opposition! We are also told that the Amorites, another nation under God’s judgement, had a long time to repent (over four generations) before they were finally destroyed. God told Abraham prior to Israel’s bondage in Egypt that his offspring would sojourn in a land not theirs for four hundred years and be servants there, for the “iniquity of the Amorites is not yet complete.”
God was patient for all that time, but the offenses had become intolerable, and God did not want the Canaanites to corrupt His people. God is sovereign over life and God used Israel to carry out His judgement. At one stage he even used Assyria to carry out His judgement on Israel, calling Assyria His rod; but Assyria was later judged as well.We see a similar command with regard to seven other nations in Deuteronomy chapter 7, where the emphasis is on breaking down their idols and avoiding intermarriage because of their corrupting influence.
The Canaanites, a very cruel nation, practiced incest, bestiality, cultic prostitution, and child sacrifice by fire. That was why Jericho was totally wiped out, apart from Rahab who helped the spies (Joshua, chapter 6). It should be noted that God commanded the Israelites to first make an offer of peace whenever they went into an enemy city.205 Does science contradict the Bible? In dealing with this question, another question has to be added, namely “Which science?” Science continually changes.