91 Hear, O Israel! You are about to cross the Jordan today, to go in and dispossess nations larger and mightier than you, great cities, fortified to the heavens, 2 a strong and tall people, the offspring of the Anakim, whom you know. You have heard it said of them, "Who can stand up to the Anakim?" 3 Know then today that the Lord your God is the one who crosses over before you as a devouring fire; he will defeat them and subdue them before you, so that you may dispossess and destroy them quickly, as the Lord has promised you. 4 When the Lord your God thrusts them out before you, do not say to yourself, "It is because of my righteousness that the Lord has brought me in to occupy this land"; it is rather because of the wickedness of these nations that the Lord is dispossessing them before you. 5 It is not because of your righteousness or the uprightness of your heart that you are going in to occupy their land; but because of the wickedness of these nations the Lord your God is dispossessing them before you, in order to fulfill the promise that the Lord made on oath to your ancestors, to Abraham, to Isaac, and to Jacob.
6 Know, then, that the Lord your God is not giving you this good land to occupy because of your righteousness; for you are a stubborn people.
Matthew Henry's Commentary on Deuteronomy 9:1-6
Commentary on Deuteronomy 9:1-6
(Read Deuteronomy 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 Ephesians 2:9,11,12.