Neither for thy upright heart, nor holy life, which are the two things which God above all things regards, 1 Chronicles 29:17 Psalms 15:1,2; and consequently he excludes all merit. And surely they who did not deserve this earthly Canaan, could not merit the kingdom of glory. That he may perform the word which he sware; to show my faithfulness in accomplishing that promise which I graciously made and confirmed with my oath. By which words it is implied, that this land was not given to them for the righteousness of their fathers, though they were righteous and holy persons, and much less for their own righteousness, which they had not, as it follows.
Related Commentaries of Deuteronomy 9:5
Deuteronomy 9:5
5 Not for thy righteousness, or for the uprightness of thine heart, dost thou go to possess their land: but for the wickedness of these nations the LORD thy God doth drive them out from before thee, and that he may perform the word which the LORD sware unto thy fathers, Abraham, Isaac, and Jacob.