Exodus 23:23 - Albert Barnes' Notes on the Bible

I will cut them off - The national existence of the Canaanites was indeed to be “utterly” destroyed, every trace of their idolatries was to be blotted out, no social contact was to be held with them while they served other gods, nor were alliances of any kind to be formed with them. (See Deuteronomy 7; Deuteronomy 12:1-4, Deuteronomy 12:29-31.) But it is alike contrary to the spirit of the divine law, and to the facts bearing on the subject scattered in the history, to suppose that any obstacle was put in the way of well disposed individuals of the denounced nations who left their sins and were willing to join the service of Yahweh. The spiritual blessings of the covenant were always open to those who sincerely and earnestly desired to possess them. See Exodus 20:10; Leviticus 19:34; Leviticus 24:22.