Thomas Aquinas — on Rom 14:10 (Commentary on Romans)

“Then when he says, but you, why do you judge, he presents the third reason, which is based on the future judgment. In regard to this he does three things: first, he suggests that a judgment at present is unnecessary, saying: but you, why do you judge, i.e., of what use or need is your judgment, your brother, rashly judging hidden matters not committed to your judgment? Or you, who are judged, why do you despise your brother, regarding as nothing the fact that you are judged by him? Why does each one despise his brother? (Mic 2:10). Second, he foretells the future judgment of Christ: As if to say: I am correct in stating why you pass judgment, because you should not fear that anyone will remain unjudged. For we shall all stand before the tribunal of Christ. The tribunal of Christ is so called on account of his judiciary power, as it says in Matthew: when the Son of man comes in his glory and all the angels with him, then he will sit on the glorious throne (Matt 25:20). He says that we shall all stand, as if to be judged, both good and evil in regard to reward or punishment: we must all appear before the judgment seat of Christ, so that each one may receive good or evil according to what he has done in the body (2 Cor 5:10). But as to the proceedings, not all will stand to be judged, but some will sit as judges: you will also sit on twelve thrones, judging the twelve tribes of Israel (Matt 19:28).”