The term "purgatory" is not found in the Bible; but neither are other such important Christian beliefs such as "Trinity" and "Incarnation." Purgatory is defined as a state of being, the continuing process of purgation or purification of the soul after human death. It is a state of perfection--begun in baptism and faith-consummated after death, entered into only by those who are saved. In other words, our transformation in Christ (Rom 13:14, "Put on the Lord Jesus Christ"), our perfection in the holiness of the Father (1 Pet 1:16, "Be holy, because I (am) holy") is not ended at our physical death. Purgatory is a sign of God's mercy on those who have honestly sought to know God and to do His will in this life and yet die in some degree of bondage to sin or the effects of sin.
The term "purgatory" itself is derived from the Latin word "purgare" which means "to purge" or "to cleanse" or "to make pure." It is the name given to that intermediate state where the souls of the dead are purified, and assisted by the prayers of the living. John the Beloved Apostle defines two kinds of sin: one that leads to eternal death, and another that is equally sin, but does not lead to eternal death:
All wrongdoing is sin, but there is sin which is not mortal." (1 John 5:7)
Jesus defines mortal or eternal sin as sin that leads to eternal damnation or death of soul:
"Whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of eternal (mortal) sin." (Mark 3:29)
Elsewhere, we are reminded that:
"Nothing unclean shall enter it (that is, the kingdom of God)." (Rev 21:27)
Paul also tells us:
"Strive for peace with all men, and for the holiness without which no one will see the Lord." (Heb 12:14)
For this reason, Christ constantly reminds us that we must strive to be without any stain of sin, whether it leads to death or not:
"You therefore must be [b]perfect as your heavenly Father is perfect." (Matt 5:45)
If indeed "nothing unclean shall enter the kingdom of heaven," and that we cannot enter heaven unless we are "perfect," "clean," and "holy" (that is, without a stain of any kind of sin including that "which is not mortal"), the question is: If a person has committed a "wrongdoing that is sin, but ... which is not mortal," and dies without having the chance of confessing this "wrongdoing which is not mortal" (that is, not leading to eternal damnation or hell), where does he go?
He cannot go to heaven because he is not yet perfect as God and all those who dwell in heaven are perfect (Matt 5:45). The stain of his wrongdoing (sin) has made him "unclean" (unfit, imperfect, unholy) to enter heaven. He cannot go to hell for his "wrongdoing (sin) is not "mortal" (does not lead to eternal damnation). Where then does he go?
He goes to purgatory where he is cleansed or purged (verb form of purgatory) of all his "wrongdoing (sins) that are not mortal," which he was not opportune to confess before he died. Consider the consequence of committing a minor "wrongdoing that is sin, but ... which is not mortal," such as looking a second longer at the vain things of the world, straying in our thoughts, uttering a "careless word:"
"I tell you, on the day of judgment men will render account of every careless word they utter." (Matt 12:36)
These are the sort of things that make us "imperfect," "unholy," "unclean" or "unfit" to enter the kingdom of heaven, but will not take us to hell. They are all "sinful wrongdoings" for which "men will render (an) account on the judgment day." Only a hypocrite will deny that they do not unavoidably encounter these minor imperfections in their daily lives. Christ was actually referring to purgatory when He said:
"Truly, I say to you, you will never get out till you have paid the last penny." (Matt 5:26)
Right. Now let us see other biblical evidence of the existence of purgatory. Paul prayed to God to have mercy on the soul of his dead friend - Onesiphorus:
"May the Lord grant him to find mercy from the Lord on that Day." (2 Tim 1:18)
Of course, Paul knew that his prayer would be useless if Onesiphorus was in heaven or hell, yet he prayed for the soul of his dead friend. That means he believed that he could be in a place other than heaven or hell.
In his letter to the Hebrews, Paul indicated the existence of purgatory as he listed the inhabitants of heaven:
"You have come to Mount Zion (the dwelling place of God - heaven) and to the city of the living God, the heavenly Jerusalem, and to innumerable angels (who were faithful during the angelic trials) in festal gathering, and to the assembly of the first-born who are enrolled in heaven (that is, those who entered heaven directly, e.g. the Blessed Virgin Mary, St. Joseph, the apostles, the martyrs, etc), and to a judge of all (probably referring to Jesus Who is both Judge and God), and to the spirits of just men made perfect (most probably, souls of righteous people who had an attachment to venial sin not properly confessed or atoned for before they died but were purified in purgatory." (Heb 12:22-23)
The dying Tobit said to his son:
"Place your bread on the grave of the righteous, but give nothing to sinners." (Tobit 4:17)
The curious question is: For what reason was this done? This was because he believed that any act of charity done for the poor had a purifying effect, which benefited departed souls.
The whole story about the existence of purgatory is told in 2 Maccabees 12:38-45. The story concludes, with unmistakable reference to purgatory in these words:
"For if he were not expecting that those who had fallen (died) would rise again, it would have been superfluous and foolish to pray for the dead. But if he was looking to the splendid reward that is laid up for those who fall asleep in godliness, it was a holy and pious thought. Therefore, he made atonement for the dead, that they might be delivered from their sin." (2 Macc 12:44-45)
Though the books of Maccabees and Tobit were rejected by the Protestant reformers and therefore are not in Protestant Bibles, one cannot ignore the historical reality of this event and the reality of the words that were said.
Sir 7:33, Isa 6:5-7, Isa 61:1, 2Macc 12:38-46, Mal 3:2-3, Mt 5:25-26,48, Mt 17:1-8, Mt 25:31-46, Lk 6:19-31,
Lk 12:58-59, 1Cor 3:12-15, 2Cor 5:10, Eph 6:18, Phil 2:10, 2Tim 1:16-18, Jam 1:12,5:19-20, Heb 9:27, Heb 12:23, 1Pet 1:3-7, 1Pet *3:13-20, 1Pet 4:6, Rev 6:9-10, Rev 21:27,22:14-15, Mark 9:48, Zechariah 13:7-9, Malachi 3:2-3