Objection 2: Further, a contrary is not cleansed save by its contrary. But punishment is not contrary to punishment. Therefore one is not cleansed from the debt of punishment by the punishment of Purgatory.
Objection 3: Further, a gloss on 1 Cor. 3:15, "He shall be saved, yet so," etc. says: "This fire is the trial of tribulation of which it is written ( Ecclus. 27:6 ): The furnace tries the potter's vessels," etc. Therefore man expiates every punishment by the pains of this world, at least by death, which is the greatest punishment of all, and not by the fire of Purgatory.
On the contrary, The pains of Purgatory are more grievous than all the pains of this world, as stated above (A[3]). Now the satisfactory punishment which one undergoes in this life atones for the debt of punishment. Much more therefore is this effected by the punishment of Purgatory.
I answer that, Whosoever is another's debtor, is freed from his indebtedness by paying the debt. And, since the obligation incurred by guilt is nothing else than the debt of punishment, a person is freed from that obligation by undergoing the punishment which he owed. Accordingly the punishment of Purgatory cleanses from the debt of punishment.
Reply to Objection 1: Although the debt of punishment does not in itself imply uncleanness, it bears a relation to uncleanness by reason of its cause.
Reply to Objection 2: Although punishment is not contrary to punishment, it is opposed to the debt of punishment, because the obligation to punishment remains from the fact that one has not undergone the punishment that was due.
Reply to Objection 3: Many meanings underlie the same words of Holy Writ. Hence this fire may denote both the present tribulation and the punishment to come, and venial sins can be cleansed from both of these. That natural death is not sufficient for this, has been stated above (Sent. iv, D, 20).
Whether one person is delivered from this punishment sooner than another?
Objection 1: It would seem that one person is not delivered from this punishment sooner than another. For the more grievous the sin, and the greater the debt, the more severely is it punished in Purgatory. Now there is the same proportion between severer punishment and graver fault, as between lighter punishment and less grievous fault. Therefore one is delivered from this punishment as soon as another.
Objection 2: Further, in point of duration unequal merits receive equal retribution both in heaven and in hell. Therefore seemingly it is the same in Purgatory.
On the contrary, is the comparison of the Apostle, who denotes the differences of venial sins by wood, hay, and stubble. Now it is clear that wood remains longer in the fire than hay and stubble. Therefore one venial sin is punished longer in Purgatory than another.
I answer that, Some venial sins cling more persistently than others, according as the affections are more inclined to them, and more firmly fixed in them. And since that which clings more persistently is more slowly cleansed, it follows that some are tormented in Purgatory longer than others, for as much as their affections were steeped in venial sins.
Reply to Objection 1: Severity of punishment corresponds properly speaking to the amount of guilt: whereas the length corresponds to the firmness with which sin has taken root in its subject. Hence it may happen that one may be delayed longer who is tormented less, and "vice versa."
Reply to Objection 2: Mortal sin which deserves the punishment of hell, and charity which deserves the reward of heaven, will, after this life, be immovably rooted in their subject. Hence as to all there is the same duration in either case. It is otherwise with venial sin which is punished in Purgatory, as stated above (A[6]).