Deuteronomy 9:6

Understand therefore that the Lord thy God giveth thee not this
good land to possess it for thy righteousness
This is again repeated to impress it upon their minds, that it was not for any goodness of theirs, but as a gift of divine goodness to them, that they were put into the possession of the good land, which greatly exceeded any merits of theirs, and was entirely owing to the kindness of God to them, and not to any righteousness of theirs; and this he frequently inculcates, that they might have a thorough understanding of it. And so the doctrines of justification by the righteousness of Christ, and not man's, and of salvation by the grace of God, and not the works of men, are points of knowledge and understanding; and to lead men into an acquaintance with them is the general design of the Gospel; and he cannot be reckoned an understanding man, but ignorant of God and his righteousness, of the law and the spirituality of it, of Christ and the way of salvation by him, of the Spirit and of spiritual things, of the Gospel and its doctrines, nor can he be wise unto salvation, who expects to get to heaven by his own works of righteousness; and it might be added, that he is ignorant of himself, of his state and condition, of his sinfulness and vileness, and of the nature of his best works; as the Israelites in a good measure seemed to be, whose conviction is laboured in the following part of this chapter:

for thou art a stiffnecked people;
refractory and unruly, like an heifer unaccustomed to the yoke, that draws back from it, and wriggles its neck out of it; so untoward and perverse were this people, and disobedient to the commands of God; wherefore there was no show of reason that they were put into the possession of Canaan for their righteousness; and to make it appear that they were such a people as here described, several instances are given.