In Catholic theology, Purgatory is a place of cleansing after the particular judgment. After death, persons who repented of their sins but had not expiated them in life are purged before entering heaven. Because everyone who enters Purgatory will eventually reach heaven, it is not some lesser form of Hell. Prayers for the dead or indulgences can shorten one's own or loved one's stays therein.
The Eastern Orthodox church does not treat the concept of Purgatory as a dogma, per se; however, they do traditionally offer prayers for the dead, asking God to show them his mercy and loving kindness. Theosis, the process of becoming more like God and more united with God, can begin in this life and can continue after death.
Protestant churches generally reject the belief in purgatory. Catholics quote II Maccabees 12:45 in defence; but Protestant do not recognise that book as canonical as it is in a group of books called by Protestants the Apocrypha and by Catholics and Orthodox the Deuterocanonical Books. Other Bible verses cited by Catholics and Orthodox are Daniel 12:10, Zechariah 13:9, Malachi 3:2-3, Matthew 5:26, Luke 12:47-48, Luke 12:58-59, 1 Corinthians 3:13-15, among others.
The Jewish Talmud speaks of Purgatory in Sabbath 33b and Rosh HaShanah 16b-17a; the Jewish belief in Purgatory and the efficacy of prayers for the dead is manifest in the Mourner's Qaddish which is prayed for 11 months after a loved one dies.