The opening paragraph of the New Catholic Encyclopedia says that the doctrine of purgatory is not found in Holy Scripture. Everybody needs to know that.

It's a papal dictate.

From the Catechism of the Catholic Church: 1032 This teaching is also based on the practice of prayer for the dead, already mentioned in Sacred Scripture: "Therefore [Judas Maccabeus] made atonement for the dead, that they might be delivered from their sin." From the beginning the Church has honored the memory of the dead and offered prayers in suffrage for them, above all the Eucharistic sacrifice, so that, thus purified, they may attain the beatific vision of God. The Church also commends almsgiving, indulgences, and works of penance undertaken on behalf of the dead: Let us help and commemorate them. If Job's sons were purified by their father's sacrifice, why would we 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.

False doctrines of demons created by men in Rome. My 2 cents.

I’m not Catholic, but it’s my belief that the concept of purgatory is based on the Judeo-Christian concept of Hell (a.k.a. Spirit Prison). While many religions teach Hell to be the antithesis of Heaven, it’s actually the antithesis of Paradise, where the faithful go to await the resurrection. My Church teaches that anyone that hasn’t fully accepted Christ in mortality cannot enter into Paradise, and thus enters into Hell. While in Hell, those that have not openly rejected Christ are given the opportunity to learn His Gospel and accept them, just as they would have been able to do if they’d had that opportunity in mortality. We that are still in mortality are then encouraged to perform Gospel ordinances on behalf of the dead, with a living individual standing as proxy. Like I said, this is *not* a Catholic perspective, but I have always assumed that this teaching is where the concept of “purgatory” (and prayers on behalf of those therein) came from.

+ Purgatory + The concept of purgation is hinted at in the Bible. Here are a few of places: "But if someone's work is burned up, that one will suffer loss; the person will be saved, but only as through fire." (1 Corinthians 3:15) "So that the genuineness of your faith, more precious than gold that is perishable even though tested by fire, may prove to be for praise, glory, and honor at the revelation of Jesus Christ." (1 Peter 1:7) But the souls of the just are in the hand of God, and no torment shall touch them. They seemed, in the view of the foolish, to be dead; and their passing away was thought an affliction and their going forth from us, utter destruction. But they are in peace. For if before men, indeed, they be punished, yet is their hope full of immortality; Chastised a little, they shall be greatly blessed, because God tried them and found them worthy of himself. As gold in the furnace, he proved them, and as sacrificial offerings he took them to himself. (Wisdom 3:1-6) Are you perfect now? Most people would say no. Will you be perfect in heaven? Most people believe yes. Purgatory (or purgation) is the process of God's love changing our imperfect selves on earth into perfect beings in heaven. Depending on the amount of change needed by different people, this can be an easy or slightly harder process. Everyone in purgatory is on his or her way to heaven. I do not think Mother Teresa of Calcutta had a very hard time of it. + Sources of Doctrine + The Catholic Church does not only use Holy Scripture for the basis of doctrine. The early Catholic church existed before and during the time that the New Testament was written (by Catholics). Catholics also believe that the Holy Spirit was guiding the early church (and is guiding the church today) to make the correct choices about things like - The Holy Trinity (which is also only hinted at in the Bible) - Going to church on Sunday instead of Saturday (which is actually directly against one of the ten commandments) - Which books to include in the New Testament? - How do our imperfect selves on earth get to be perfect in heaven? This second source of doctrine is called Apostolic Tradition. For more information, see the Catechism of the Catholic Church, section 1030: http://www.usccb.org/catechism/text/pt1sect2chpt3art12.htm#1030 + With love in Christ.

I'm not sure the question has been answered yet, so here goes from what a Lutheran professor taught me: The whole structure of purgatory was built up like an upside-down pyramid on a single statement by Saint Monica, mother of Augustine: she asked him to pray for her after her death. This led theologians to ask why, and conjecture answers, and then to look for things to back up their conjectures. In other words, if that professor is right, the teaching of purgatory didn't even begin to exist until the fourth century.

The doctrine of the Catholic faith regarding Purgatory, like all Catholic doctrines, is to be believed because it is taught by the One, Holy, Catholic, Apostolic Church that Jesus himself founded. We Catholics walk by faith and not by sight. We preach Christ crucified. Jesus set up One infallible Church teaching one faith (Matt 16, Eph 4) with his authority (John 20, Matt 28). One either accepts the authority of the Catholic Church in matters of faith and morals, or one does not. The acceptance or rejection of the teaching of the Church is the decision of the individual by an exercise of his or her free will. Nevertheless, whatever this or that person believes or refuses does not change the ontological truth or authority of the Catholic Church one bit. In summary, the teaching of Purgatory is a doctrine of the Faith because the Catholic Church teaches it -- the same Catholic Church that gave the world the Bible and preserved it -- and the same Catholic Church that Christ himself promised the Holy Spirit would be sent to in order to guide it into all truth.