The tradition of the Jews is put forth with precision and clearness in II Maccabees. Judas, the commander of the forces of Israel, "making a gathering . . . sent twelve thousand drachmas of silver to Jerusalem for sacrifice to be offered for the sins of the dead, thinking well and religiously concerning the resurrection (For if he had not hoped that they that were slain should rise again, it would have seemed superfluous and vain to pray for the dead). And because he considered that they who had fallen asleep with godliness, had great grace laid up for them. "It is therefore a holy and wholesome thought to pray for the dead, that they may be loosed from sins" (II Mach., xii, 43-46). At the time of the Maccabees the leaders of the people of God had no hesitation in asserting the efficacy of prayers offered for the dead, in order that those who had departed this life might find pardon for their sins and the hope of eternal resurrection.
New Testament
There are several passages in the New Testament that point to a process of purification after death. Thus, Jesus Christ declares (Matthew 12:32): "And whosoever shall speak a word against the Son of man, it shall be forgiven him: but he that shall speak against the Holy Ghost, it shall not be forgiven him, neither in this world, nor in the world to come." According to St. Isidore of Seville (Deord. creatur., c. xiv, n. 6) these words prove that in the next life "some sins wil be forgiven and purged away by a certain purifying fire." St. Augustine also argues "that some sinners are not forgiven either in this world or in the next would not be truly said unless there were other [sinners] who, though not forgiven in this world, are forgiven in the world to come" (De Civ. Dei, XXI, xxiv). The same interpretation is given by Gregory the Great (Dial., IV, xxxix); St. Bede (commentary on this text); St. Bernard (Sermo lxvi in Cantic., n. 11) and other eminent theological writers.
A further argument is supplied by St. Paul in I Cor., iii, 11-1,5: "For other foundation no man can lay, but that which is laid; which is Christ Jesus. Now if any man build upon this foundation, gold, silver, precious stones, wood, hay stubble: Every man's work shall be manifest; for the day of the Lord shall declare it, because it shall be revealed in fire; and the fire shall try every man's work, of what sort it is. If any man's work abide, which he hath built thereupon, he shall receive a reward. If any man's work burn, he shall suffer loss: but he himself shall be saved, yet so as by fire." While this passage presents considerable difficulty, it is regarded by many of the Fathers and theologians as evidence for the existence of an intermediate state in which the dross of lighter transgressions will be burnt away, and the soul thus purified will be saved. This, according to Bellarmine (De Purg., I, 5), is the interpretation commonly given by the Fathers and theologians; and he cites to this eftect.
Old Testament
The tradition of the Jews is put forth with precision and clearness in II Maccabees. Judas, the commander of the forces of Israel, "making a gathering . . . sent twelve thousand drachmas of silver to Jerusalem for sacrifice to be offered for the sins of the dead, thinking well and religiously concerning the resurrection (For if he had not hoped that they that were slain should rise again, it would have seemed superfluous and vain to pray for the dead). And because he considered that they who had fallen asleep with godliness, had great grace laid up for them. "It is therefore a holy and wholesome thought to pray for the dead, that they may be loosed from sins" (II Mach., xii, 43-46). At the time of the Maccabees the leaders of the people of God had no hesitation in asserting the efficacy of prayers offered for the dead, in order that those who had departed this life might find pardon for their sins and the hope of eternal resurrection.
New Testament
There are several passages in the New Testament that point to a process of purification after death. Thus, Jesus Christ declares (Matthew 12:32): "And whosoever shall speak a word against the Son of man, it shall be forgiven him: but he that shall speak against the Holy Ghost, it shall not be forgiven him, neither in this world, nor in the world to come." According to St. Isidore of Seville (Deord. creatur., c. xiv, n. 6) these words prove that in the next life "some sins wil be forgiven and purged away by a certain purifying fire." St. Augustine also argues "that some sinners are not forgiven either in this world or in the next would not be truly said unless there were other [sinners] who, though not forgiven in this world, are forgiven in the world to come" (De Civ. Dei, XXI, xxiv). The same interpretation is given by Gregory the Great (Dial., IV, xxxix); St. Bede (commentary on this text); St. Bernard (Sermo lxvi in Cantic., n. 11) and other eminent theological writers.
A further argument is supplied by St. Paul in I Cor., iii, 11-1,5: "For other foundation no man can lay, but that which is laid; which is Christ Jesus. Now if any man build upon this foundation, gold, silver, precious stones, wood, hay stubble: Every man's work shall be manifest; for the day of the Lord shall declare it, because it shall be revealed in fire; and the fire shall try every man's work, of what sort it is. If any man's work abide, which he hath built thereupon, he shall receive a reward. If any man's work burn, he shall suffer loss: but he himself shall be saved, yet so as by fire." While this passage presents considerable difficulty, it is regarded by many of the Fathers and theologians as evidence for the existence of an intermediate state in which the dross of lighter transgressions will be burnt away, and the soul thus purified will be saved. This, according to Bellarmine (De Purg., I, 5), is the interpretation commonly given by the Fathers and theologians; and he cites to this eftect:
PURGATORY: C.S. Lewis (Protestant):
Of course I pray for the dead. At our age the majority of those we love best are dead. What sort of intercourse with God could I have if what I love best were unmentionable to Him? I believe in purgatory. Our souls demand purgatory, don't they? My favourite image on this matter comes from the dentist's chair. I hope that when the tooth of life is drawn, a voice will say, 'Rinse your mouth out with this.' This will be purgatory. {Letters to Malcolm: Chiefly on Prayer, 107-109}
The notion that our destiny is fixed at the precise point of death is not clear in the Bible. We know we are judged, but this does not preclude purgatory, which is simply a portion of that entire process. Nothing in the Bible indicates that either God's work of grace in us or judgment is speedily completed upon death. We do not even know for sure the ultimate salvation or damnation of anyone. Thus, it follows that we can pray for the souls of all men, and commend them to God's grace and mercy. On the other hand, there is much indication in the Bible in favor of some notion of purgatory, to be seen below.
Most of us end our earthly sojourn far short of sainthood and yet not utterly within the grips of sin. Moreover, some who have been notoriously wicked repent at the last moment (e.g., the thief on the cross), and God will not reject any penitent sinner. Such a death-bed penitent must atone for his life-long transgressions. Nothing defiled can enter heaven. But it would seem that anyone in the "friendship" of God would not deserve the fate of eternal hellfire. Hence, there must exist some process of purgation by which man is fashioned into a creature worthy of entrance into the all-holy presence of God.
Seen in this light, purgatory, contrary to the Protestant horror of it, is actually one of the most merciful aspects of God's love for us, and very consoling to the human heart. Since, in Catholic doctrine, sin is real and must be truly eradicated, not just "covered up," as in Protestantism, a change must occur in all of us sinners after death. Purgatory alone retains both God's loving and holy attributes as pertaining to the Judgment of each human being. A patient who has the assurance of recovery willingly endures the surgeon's knife or other unpleasant remedies. Purgatory is the vestibule of heaven. All of its sufferings are inflicted and endured in love.
The Catholic Church has not declared dogmatically whether or not there is "fire" in purgatory, and the "fire" might be metaphorical, yet the idea of refinement is present either way. There is no comparison between the sufferings in purgatory and those in hell. That in purgatory is temporary, is full of assured hope, it is willingly borne with resolve and patience, and accompanied with intense spiritual joy. The souls in purgatory can also pray and obtain blessings for those on earth, with great charity commensurate with their relative closeness to God.
C.S. Lewis is a Protestant and a brilliant literary giant, but I do not read him for systematic theology.
As to the NT Quotes:
The sin against the Holy Spirit. I see no mention of purging fires (as does St. Isidore) nor do I agree with the implication of Augustine (et al.) from the biblical statement that this corrollary is implied. Slim speculation I'd say, even though I consider Augustine, Gregory, etc. serious students of Scripture. Virtually all of Protestant scholarship does not embrace their deduction.
Regarding the 1 Corinthian 3 passage the issue in is reward or loss of reward not forgiveness. How does this text prove an intermediate state? I see this as the same event as the judgment seat of Christ (the bema) in Romans 14:10.
Other Points:
[1] Protestants do not teach sins are covered up after the death of Christ. The Day of Atonement in the OT was indeed a covering of sins looking forward to the final sacrifice of Christ. Christ paid the full legal penalty for my sins by dying in my place. By faith I am declared rightewous and there is no condemnation for those in Christ Jesus.
[2]RC theology, IMHO, confuses justification and sanctification. Justification comes as we receive the GIFT of eternal (not conditional) life. Sanctification is the basis for REWARD. The difference between gift and reward is crucial.
[3] The Bible says "these things were written that you may know that you have eternal life." RC theology, if I am not mistaken, does teach that the Pope by special revelation is assurred of his eternal destiny. In any case, I think the NT gives more warrant for a believer's assurrance than you might think.
I know you see these issues differently -- and I have not taken the time to write a detailed response. Yet hopefully these thoughts give some indication of why I have such a confidence in the One who said "It is finished," in Whom I have put my full trust for forgiveness and Whom fully bore my guilt and my shame. Such assurrance humbles me and makes me want to serve Him as a way of expressing my gratitude. Fear has given way to overwhelming appreciation.
I wish you God's blessings and respect the sincerity of your beliefs.