Objection 1. It would seem that none of the good will be judged at the judgment. For it is declared (John 3:18) that "he that believeth in Him is not judged." Now all the good believed in Him. Therefore they will not be judged.
Objection 2. Further, those who are uncertain of their bliss are not blessed: whence Augustine proves (Gen. ad lit. xi) that the demons were never blessed. But the saints are now blessed. Therefore they are certain of their bliss. Now what is certain is not submitted to judgment. Therefore the good will not be judged.
Objection 3. Further, fear is incompatible with bliss. But the last judgment, which above all is described as terrible, cannot take place without inspiring fear into those who are to be judged. Hence Gregory observes on Job 41:16 "When he shall raise him up, the angels shall fear," etc. (Moral. xxxiv): "Consider how the conscience of the wicked will then be troubled when even the just are disturbed about their life." Therefore the blessed will not be judged.
On the contrary, It would seem that all the good will be judged, since it is written (2 Corinthians 5:10): "We must all be manifested before the judgment seat of Christ, that every one may receive the proper things of the body, according as he hath done, whether it be good or evil." Now there is nothing else to be judged. Therefore all, even the good, will be judged.
Further, the "general" includes all. Now this is called the general judgment. Therefore all will be judged.
I answer that, The judgment comprises two things, namely the discussion of merits and the payment of rewards. As regards the payment of rewards, all will be judged, even the good, since the Divine sentence will appoint to each one the reward corresponding to his merit. But there is no discussion of merits save where good and evil merits are mingled together. Now those who build on the foundation of faith, "gold, silver, and precious stones" (1 Corinthians 3:12), by devoting themselves wholly to the Divine service, and who have no notable admixture of evil merit, are not subjected to a discussion of their merits. Such are those who have entirely renounced the things of the world and are solicitously thoughtful of the things that are of God: wherefore they will be saved but will not be judged. Others, however, build on the foundation of faith, wood, hay, stubble [Cf. I-II, 89, 2]; they, in fact, love worldly things and are busy about earthly concerns, yet so as to prefer nothing to Christ, but strive to redeem their sins with alms, and these have an admixture of good with evil merits. Hence they are subjected to a discussion of their merits, and consequently in this account will be judged, and yet they will be saved.
Reply to Objection 1. Since punishment is the effect of justice, while reward is the effect of mercy, it follows that punishment is more especially ascribed antonomastically to judgment which is the act of justice; so that judgment is sometimes used to express condemnation. It is thus that we are to understand the words quoted, as a gloss on the passage remarks.
Reply to Objection 2. The merits of the elect will be discussed, not to remove the uncertainty of their beatitude from the hearts of those who are to be judged, but that it may be made manifest to us that their good merits outweigh their evil merits, and thus God's justice be proved.
Reply to Objection 3. Gregory is speaking of the just who will still be in mortal flesh, wherefore he had already said: "Those who will still be in the body, although already brave and perfect, yet through being still in the flesh must needs be troubled with fear in the midst of such a whirlwind of terror." Hence it is clear that this fear refers to the time immediately before the judgment, most terrible indeed to the wicked, but not to the good, who will have no apprehension of evil. The arguments in the contrary sense consider judgment as regards the payment of rewards.
Source: Summa Theologica (New Advent)