16 You know how we lived in the land of Egypt, and how we came through the midst of the nations through which you passed. 17 You have seen their detestable things, the filthy idols of wood and stone, of silver and gold, that were among them. 18 It may be that there is among you a man or woman, or a family or tribe, whose heart is already turning away from the Lord our God to serve the gods of those nations. It may be that there is among you a root sprouting poisonous and bitter growth. 19 All who hear the words of this oath and bless themselves, thinking in their hearts, "We are safe even though we go our own stubborn ways" (thus bringing disaster on moist and dry alike) - 20 the Lord will be unwilling to pardon them, for the Lord's anger and passion will smoke against them. All the curses written in this book will descend on them, and the Lord will blot out their names from under heaven.
Matthew Henry's Commentary on Deuteronomy 29:16-20
Commentary on Deuteronomy 29:10-21
(Read Deuteronomy 29:10-21)
The national covenant made with Israel, not only typified the covenant of grace made with true believers, but also represented the outward dispensation of the gospel. Those who have been enabled to consent to the Lord's new covenant of mercy and grace in Jesus Christ, and to give up themselves to be his people, should embrace every opportunity of renewing their open profession of relation to him, and their obligation to him, as the God of salvation, walking according thereto. The sinner is described as one whose heart turns away from his God; there the mischief begins, in the evil heart of unbelief, which inclines men to depart from the living God to dead idols. Even to this sin men are now tempted, when drawn aside by their own lusts and fancies. Such men are roots that bear gall and wormwood. They are weeds which, if let alone, overspread the whole field. Satan may for a time disguise this bitter morsel, so that thou shalt not have the natural taste of it, but at the last day, if not before, the true taste shall be discerned. Notice the sinner's security in sin. Though he hears the words of the curse, yet even then he thinks himself safe from the wrath of God. There is scarcely a threatening in all the book of God more dreadful than this. Oh that presumptuous sinners would read it, and tremble! for it is a real declaration of the wrath of God, against ungodliness and unrighteousness of man.