23 It is precisely the scheme and system thus laid down in the Gospel that the Prophet has followed, when he says: Therefore the ungodly shall not rise again in the Judgement, nor sinners in the counsel of the righteous. He leaves no judgment for the ungodly, because they have been judged already; on the other hand, he has refused to sinners, who as we showed in our former discourse are to be distinguished from the ungodly, the counsel of the righteous, because they are to be judged. For ungodliness causes the former to be judged beforehand, but sin keeps the latter to be judged hereafter. Thus ungodliness having already been judged is not admitted to the judgment of sinners, while again sinners, who, are yet to be judged, are deemed unworthy of enjoying the counsel of the righteous, who will not be judged.
Source: Homilies on the Psalms (New Advent)