Objection 1. It would seem that none of the wicked will be judged. For even as damnation is certain in the case of unbelievers, so is it in the case of those who die in mortal sin. Now it is declared because of the certainty of damnation (John 3:18): "He that believeth not is already judged." Therefore in like manner neither will other sinners be judged.
Objection 2. Further, the voice of the Judge is most terrible to those who are condemned by His judgment. Now according to the text of Sentent. iv, D, 47 and in the words of Gregory (Moral. xxvi) "the Judge will not address Himself to unbelievers." If therefore He were to address Himself to the believers about to be condemned, the unbelievers would reap a benefit from their unbelief, which is absurd.
On the contrary, It would seem that all the wicked are to be judged, because all the wicked will be sentenced to punishment according to the degree of their guilt. But this cannot be done without a judicial pronouncement. Therefore all the wicked will be judged.
I answer that, The judgment as regards the sentencing to punishment for sin concerns all the wicked. whereas the judgment as regards the discussion of merits concerns only believers. Because in unbelievers the foundation of faith is lacking, without which all subsequent works are deprived of the perfection of a right intention, so that in them there is no admixture of good and evil works or merits requiring discussion. But believers in whom the foundation of faith remains, have at least a praiseworthy act of faith, which though it is not meritorious without charity, yet is in itself directed to merit, and consequently they will be subjected to the discussion of merits. Consequently, believers who were at least counted as citizens of the City of God will be judged as citizens, and sentence of death will not be passed on them without a discussion of their merits; whereas unbelievers will be condemned as foes, who are wont among men to be exterminated without their merits being discussed.
Reply to Objection 1. Although it is certain that those who die in mortal sin will be damned, nevertheless since they have an admixture of certain things connected with meriting well, it behooves, for the manifestation of Divine justice, that their merits be subjected to discussion, in order to make it clear that they are justly banished from the city of the saints, of which they appeared outwardly to be citizens.
Reply to Objection 2. Considered under this special aspect the words addressed to the believers about to be condemned will not be terrible, because they will reveal in them certain things pleasing to them, which it will be impossible to find in unbelievers, since "without faith it is impossible to please God" (Hebrews 11:6). But the sentence of condemnation which will be passed on them all will be terrible to all of them.
The argument in the contrary sense considered the judgment of retribution.
Source: Summa Theologica (New Advent)