9:1-6 Moses represents the strength of the enemies they were now to encounter. This was to drive them to God, and engage their hope in him. He assures them of victory, by the presence of God with them. He cautions them not to have the least thought of their own righteousness, as if that procured this favour at God's hand. In Christ we have both righteousness and strength; in Him we must glory, not in ourselves, nor in any sufficiency of our own. It is for the wickedness of these nations that God drives them out. All whom God rejects, are rejected for their own wickedness; but none whom he accepts are accepted for their own righteousness. Thus boasting is for ever done away: see Eph 2:9,11,12.

4-6. Speak not thou in thine heart, … saying, For my righteousness the Lord hath brought me in to possess this land—Moses takes special care to guard his countrymen against the vanity of supposing that their own merits had procured them the distinguished privilege. The Canaanites were a hopelessly corrupt race, and deserved extermination; but history relates many remarkable instances in which God punished corrupt and guilty nations by the instrumentality of other people as bad as themselves. It was not for the sake of the Israelites, but for His own sake, for the promise made to their pious ancestors, and in furtherance of high and comprehensive purposes of good to the world, that God was about to give them a grant of Canaan.