John Chrysostom

"In flaming fire rendering vengeance to them that know not God, and to them that obey not the Gospel of our Lord Jesus."

If they that have not obeyed the Gospel suffer vengeance, what will not they suffer who besides their disobedience also afflict you? And see his intelligence; he says not here those who afflict you, but those "who obey not." So that although not on your account, yet on His own it is necessary to punish them. This then is said in order to full assurance, that it is altogether necessary for them to be punished: but what was said before, was said that they also might be honored, because they suffer these things on your account. The one causes them to believe concerning the punishment; the other to be pleased, because for the sake of what has been done to them they suffer these things.