In Deuteronomy, chapter nine, verse four, the nations of Canaan experience destruction by God because of their extreme wickedness. Their corruption was so terrible and widespread that God determined they had to remove them like dreaded cancer. In this manner, Israel’s conquest and extermination of the Canaanites were capital punishment on a national level. Likewise, virtually uncontrolled wickedness existed in Noah’s day and will characterize the world at the end of time.
The Israelite’s victory over the Canaanites was not done by their human plan but by the mighty hand of God. The people are not to speak in their hearts or never once think within themselves or give way to such a vain imagination. The Lord God cast the Canaanites out to make way for the Israelites and put them into the possession of the land. Saying that their righteousness is why the Lord brought them to possess this land would be wrong. Such thought as this was not to be cherished in their hearts and much less expressed with their lips.
Nothing more foreign from the truth than this and yet a notion they were prone to entertain. There will always be people, more or less, from first to last, tainted with a conceit of their righteousness and goodness, which they labored to establish, and were ready to attribute all the good things to it they enjoyed. Nothing is more natural to people than to fancy fairness, which is contrary to the perfections of God, his purity, holiness, and justice, which can never admit of an imperfect righteousness in the room of a perfect one.
The wickedness of these nations, the Lord drives them out from before the Israelites. Namely, their idolatry, incest, and other notorious crimes are stated in Leviticus eighteen verse three, which sufficiently justifies God in all his dealings with these nations.