91 Hear, Israel! Thou art to pass over the Jordan this day, to enter in to possess nations greater and mightier than thou, cities great and walled up to heaven, 2 a people great and tall, the sons of the Anakim, whom thou knowest, and of whom thou hast heard [say], Who can stand before the sons of Anak! 3 Know then this day, that Jehovah thy God is he that goeth over before thee, a consuming fire; he will destroy them, and he will cast them down before thee, and thou shalt dispossess them and cause them to perish quickly, as Jehovah hath said unto thee. 4 Thou shalt not say in thy heart, when Jehovah thy God thrusteth them out from before thee, saying, For my righteousness Jehovah hath brought me in to possess this land; but for the wickedness of these nations doth Jehovah dispossess them from before thee. 5 Not for thy righteousness, or for the uprightness of thy heart, dost thou enter in to possess their land, but for the wickedness of these nations doth Jehovah thy God dispossess them from before thee, and that he may perform the word which Jehovah swore unto thy fathers, to Abraham, to Isaac, and to Jacob.
6 Know therefore that Jehovah thy God doth not give thee this good land to possess it for thy righteousness; for thou art a stiff-necked 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.