The ancient Fathers, Origen in the third century, St. Ambrose and St. Jerome in the fourth, and St. Augustine in the fifth, have interpreted this text of St. Paul as relating to venial sins committed by Christians which St. Paul compares to "wood, hay, stubble," and thus with this text they confirm the Catholic belief in Purgatory, well known and believed in their time, as it is by Catholics in the present time. In St. Matthew (chap. v. 25, 26) we read, "Be at agreement with thy adversary betimes, whilst thou art in the way with him; lest, perhaps, the adversary deliver thee to the judge, and the judge deliver thee to the officer, and thou be cast into prison. Amen, I say to thee, thou shalt not go out from thence till thou repay the last farthing."
On this passage, St. Cyprian, Bishop of Carthage, a Father of the third century, says: "It is one thing to be cast into prison, and not go out from thence till the last farthing be paid, and another to receive at once the reward of faith and virtue: one thing in punishment of sin to be purified by long-suffering and purged by long fire, and another to have expiated all sins of suffering (in this life); one in fire, at the day of Judgment to wait the sentence of the Lord, another to receive an immediate crown from Him." (Epist. iii.)
Our Saviour said: "He that shall speak against the Holy Ghost, it shall not be forgiven him in this world, nor in the world to come." (St. Matt. xii. 32.)
From this text St. Augustine argues, that "It would not have been said with truth that their sin shall not be forgiven, neither in this world, nor in the world to come, unless some sins were remitted in the next world." (De Civitate Dei, Book xxi. chap. 24.)
On the other hand, we read in several places in Holy Scripture that God will render to every one (that is, will reward or punish) according as each deserves. See, for example, in Matthew xvi. 27. But as we cannot think that God will punish everlastingly a person who dies burdened with the guilt of venial sin only, it may be an "idle word," it is reasonable to infer that the punishment rendered to that person in the next world will be only temporary.
The Catholic belief in Purgatory does not clash with the following declarations of Holy Scripture, which every Catholic firmly believes, namely, that it is Jesus who cleanseth us from all sin, that Jesus bore "the iniquity of us all," that "by His bruises we are healed," (Isaias iii., 5); for it is through the blood of Jesus and His copious Redemption that those pains of Purgatory have power to cleanse the souls therein detained.
Again, the Catholic belief in Purgatory is not in opposition to those texts of Scripture in which it is said that a man when he is justified is "translated from death to life;" that he is no longer judged: that there is no condemnation in him. For these passages do not refer to souls taken to Heaven when natural death occurs, but to persons in this world, who from the death of sin pass to the life of grace. Nor does it follow that dying in that state of grace, that is, in a state of spiritual life, they must go at once to Heaven. A soul may be justified, entirely exempt from eternal condemnation, and yet have something to suffer for a time; thus, also, in this world, many are justified, and yet are not exempt from suffering.
Again, it is not fair to bring forward against the Catholic doctrine on Purgatory that text of the Apocalypse, Rev. xix. 13: "Blessed are the dead, who die in the Lord. From henceforth now, saith the Spirit, that they may rest from their labors: for their works follow them," for this text applies only to those souls who die perfectly in the Lord, that is, entirely free from every kind of sin, and from the stain, the guilt, and the debt of temporal punishment of every sin. Catholics believe that these souls have no pain to suffer in Purgatory, as is the case with the martyrs and saints who die in a perfect state of grace.
It is usual to bring forward against the Catholic belief in Purgatory that text which says: "If the tree fall to the south, or to the north, in what place soever it shall fall, there shall it be." (Eccles. xi. 3.)
This text confirms and illustrates the truth that, when death comes, the final doom of every one is fixed, and that there is no possibility of changing it; so that one dying in a state of mortal sin will always remain in a state of mortal sin, and consequently be rejected forever; and one dying in a state of grace and friendship with God, will forever remain accepted by God and in a state of grace, and in friendship with Him.