John Calvin Commentary Deuteronomy 29:20

"Jehovah will not pardon him, but then the anger of Jehovah and his jealousy will smoke against that man, and all the curse that is written in this book shall lie upon him, and Jehovah will blot out his name from under heaven." — Deuteronomy 29:20 (ASV)

The Lord will not spare him. Moses here teaches us that the obstinacy in which the wicked are willfully hardened shuts the door of hope against them, so that they will find that God is not to be appeased.

Assuredly, it is the climax of all sins when a wretched man, abandoned to vice, extinguishes the light of his own reason and destroys the image of God within him, degenerating into a beast. Not only this, but he also dethrones God, as if God were not the Judge of the world. This is the insult they offer Him when they abandon themselves to sin in the confident expectation of impunity.²⁷³

Thus, through Isaiah, God swears that this was an inexpiable crime: when He called them to baldness and mourning, the Israelites encouraged each other to gladness and, while feasting luxuriously, said in ridicule, “Tomorrow we shall die” (Isaiah 22:12–13).

By the word אבה (ahab), Moses altogether shuts out the grace of God.²⁷⁴ Meanwhile, he contrasts God’s fixed purpose—that He will not be willing to pardon—with the depraved pleasures of those who take too much delight in their sins.

See, then, what poor sinners gain by their proud contempt when they endeavor to cast off God’s judgment together with His fear!

Furthermore, to better express that God will be irreconcilable to such great perversity, Moses declares that He will exterminate from the earth those who have so wantonly exulted in iniquity; and he finally adds that He will give them up to be accursed (in anathemata), so that they will no longer hold a place among the people of Israel. Now, it is a much more grievous thing to be cut off from the elect people and to be set apart for evil, as it is said here, than to be deprived of natural life.

²⁷³ “Car ceux qui sous ombre d’eschapper son jugement s’abandonnent ‘a pecher, luy font ce dishonneur de le despouiller de son empire;” for those who abandon themselves to sin under cover of escaping His judgment, do him this dishonor of despoiling him of his empire. — Fr..

²⁷⁴ “Le verbe que nous avons translate condescendre, signifie venir a gre. Ainsi Moyse exclud toutes graces de Dieu;” the verb which we have translated condescend, (the Lord will not condescend to spare him,) signifies to consent. Thus Moses shuts out all the graces of God. — Fr יאבה, acquiescet. — Taylor.