Since the topic was brought up in the midst of the baptism discussion, I’ll take a small detour and talk about purgatory, one of many Catholic teachings that are easily misunderstood.
First off, purgatory takes up a small portion of the Catechism, only three paragraphs. The teaching on purgatory is found in the first section of the Catechism I skipped over, which is the Profession of Faith based on the Apostles’ Creed. It falls under the Article “I believe in life everlasting.”
The Catechism states, “All who die in God’s grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven,” (CCC 1030). This purification’s name is Purgatory, and was formulated primarily at the Councils of Florence and Trent during the Middle Ages. “The tradition of the Church, by reference to certain texts of Scripture, speaks of a cleansing fire,” (CCC 1031). Those Scripture references listed are 1 Corinthians 3:15 and 1 Peter 1:7:
By the grace God has given me, I laid a foundation as an expert builder, and someone else is building on it. But each one should be careful how he builds. For no one can lay any foundation other than the one already laid, which is Jesus Christ. If any man builds on this foundation using gold, silver, costly stones, wood, hay or straw, his work will be shown for what it is, because the Day will bring it to light. It will be revealed with fire, and the fire will test the quality of each man's work. If what he has built survives, he will receive his reward. If it is burned up, he will suffer loss; he himself will be saved, but only as one escaping through the flames. (1 Cor 3:10-15, NIV, biblegateway.com)
These [trials] have come so that your faith—of greater worth than gold, which perishes even though refined by fire—may be proved genuine and may result in praise, glory and honor when Jesus Christ is revealed. (1 Peter 1:7)
Pope St. Gregory the Great comments on this as well:
“As for certain lesser faults, we must believe that, before the Final Judgment, there is a purifying fire. He who is truth says that whoever utters blasphemy against the Holy Spirit will be pardoned neither in this age nor in the age to come. From this sentence we understand that certain offenses can be forgiven in this age, but certain others in the age to come.” (St. Gregory the Great, 600s AD)
My understanding of this is that most do not die in perfect, holy communion with God, there is still the effect of sin on us. Purgatory cleanses us from this before we enter heaven. An analogy I heard is that Purgatory is like being able to smell heaven’s goodness and scent, yet we are not quite ready for it yet. It is not a place of neutrality; people judged for hell have already set themselves against God. The same is true of those bound for heaven. But because God is all holy, we ourselves must become pure and holy to enter His presence.
Prayers for the dead and masses are based on a Catholic biblical book, 2 Maccabees. This book is not found in the Protestant canon, though Bibles with deuterocanonical/apocryphal books would have this one.
He then took up a collection among all his soldiers, amounting to two thousand silver drachmas, which he sent to Jerusalem to provide for an expiatory sacrifice. In doing this he acted in a very excellent and noble way, inasmuch as he had the resurrection of the dead in view; for if he were not expecting the fallen to rise again, it would have been useless and foolish to pray for them in death. But if he did this with a view to the splendid reward that awaits those who had gone to rest in godliness, it was a holy and pious thought. Thus he made atonement for the dead that they might be freed from this sin. – 2 Macc. 12:43-46
St. John Chrysostom wrote about this as well in his lifetime (347-407 AD):
Let us help and commemorate them. If Job’s sons were purified by their father’s sacrifice, why would be doubt that our offerings for the dead bring them some consolation? Let us not hesitate to help those who have died and to offer our prayers for them.
To be honest, this part I have not fully come to terms with. My struggle is that after our death, time would cease to have meaning. So then, how can a time be put on our time in purgatory? Ultimately, we do not know what exactly happens after our death. What we do know is that God will judge us and we will be separated like sheep and goats (Matthew 25:31-46).