2 Thessalonians 1:8

8Who will inflict vengeance. That he may the better persuade believers that the persecutions which they endure will not go unpunished, he teaches that this also involves the interests of God himself, inasmuch as the same persons that persecute the pious are guilty of rebellion against God. Hence it is necessary that God should inflict vengeance upon them not merely with a view to our salvation, but also for the sake of his own glory. Farther, this expression, who will inflict vengeance, relates to Christ, for Paul intimates that this office is assigned to him by God the Father. It may be asked, however, whether it is lawful for us to desire vengeance, for Paul promises it, as though it could be lawfully desired. I answer, that it is not lawful to desire vengeance upon any one, inasmuch as we are commanded to wish well to all. Besides, although we may in a general way desire vengeance upon the wicked, yet, as we do not as yet discriminate them, we ought to desire the welfare of all. In the mean time, the ruin of the wicked may be lawfully looked forward to with desire, provided there reigns in our hearts a pure and duly regulated zeal for God, and there is no feeling of inordinate desire.

Who know not. He distinguishes unbelievers by these two marks — that they know not God, and obey not the gospel of Christ. For if obedience is not rendered to the gospel through faith, as he teaches in the first and in the last chapters of the Epistle to the Romans, [Romans 1:18,] unbelief is the occasion of resistance to it. He charges them at the same time with ignorance of God, for a lively acquaintance with God produces of itself reverence towards him. Hence unbelief is always blind, not as though unbelievers were altogether devoid of light and intelligence, but because they have the understanding darkened in such a manner, that seeing they do not see. (Matthew 13:13.) It is not without good grounds that Christ declares that this is life eternal, to know the true God, etc. (John 17:3.) Accordingly, from the want of this salutary knowledge, there follows contempt of God, and in fine, death. On this point I have treated more fully in commenting on the first chapter of First Corinthians. (632)