Deuteronomy 7:2-6

thou shalt smite them, and utterly destroy them; thou shalt make no covenant with them—This relentless doom of extermination which God denounced against those tribes of Canaan cannot be reconciled with the attributes of the divine character, except on the assumption that their gross idolatry and enormous wickedness left no reasonable hope of their repentance and amendment. If they were to be swept away like the antediluvians or the people of Sodom and Gomorrah, as incorrigible sinners who had filled up the measure of their iniquities, it mattered not to them in what way the judgment was inflicted; and God, as the Sovereign Disposer, had a right to employ any instruments that pleased Him for executing His judgments. Some think that they were to be exterminated as unprincipled usurpers of a country which God had assigned to the posterity of Eber and which had been occupied ages before by wandering shepherds of that race, till, on the migration of Jacob's family into Egypt through the pressure of famine, the Canaanites overspread the whole land, though they had no legitimate claim to it, and endeavored to retain possession of it by force. In this view their expulsion was just and proper. The strict prohibition against contracting any alliances with such infamous idolaters was a prudential rule, founded on the experience that "evil communications corrupt good manners" [I Corinthians 15:33], and its importance or necessity was attested by the unhappy examples of Solomon and others in the subsequent history of Israel.