Matthew Henry on Deuteronomy 29:22-28

Idolatry would be the ruin of their nation. It is no new thing for God to bring desolating judgments on a people near to him in profession. He never does this without good reason. It concerns us to seek for the reason, that we may give glory to God, and take warning to ourselves. Thus the law of Moses leaves sinners under the curse, and rooted out of the Lord's land; but the grace of Christ toward penitent, believing sinners, plants them again in their land; and they shall no more be pulled up, being kept by the power of God.