In Christian eschatology, the intermediate state or interim state refers to a person's existence between one's death and resurrection. This period is "intermediate" between death and the last judgment.
As long as Christians looked for an imminent end of the world, they had little interest in an interim state between death and resurrection. Later, the Eastern Church came to admit of such an intermediate state, but refrained from defining it, so as not to blur the distinction between the alternative definitive fates of heaven and hell. In the West there was much more curiosity about the intermediate state, with evidence from as far back as the Passion of Saints Perpetua and Felicity (203) of the belief that sins can be purged by suffering in an afterlife, and that the purgation can be speeded up by the prayers of the living. Eastern Christians too believed that the dead can be assisted by prayer.
East and West, those in the intermediate state have traditionally been the beneficiaries of prayers, such as requiem masses. In the East, the saved are said to rest in light while the wicked are confined in darkness. In the East, prayers are said to benefit even pagans. In the West, Augustine described prayer as useful for those in communion with the church, and implied that every soul's ultimate fate is determined at death. In the West, prayer came to be restricted to souls in purgatory. In the Middle Ages, the Western church offered indulgences for those in purgatory. Protestants largely ceased praying for the dead.
Protestants denied the Catholic purgatory. Luther posited "soul sleep", in which the soul is asleep, yet "lives before God" and "experiences visions and the discourses of the angels and of God". Calvin depicted the righteous dead as resting in bliss.
The gospel of Luke describes hades along the lines of Jewish sheol, divided between the happy righteous and the miserable wicked. Early Christians described hades as the underworld where all the souls of the dead were kept until the resurrection. Hippolytus described hades with a two-way division, with the lake of fire from Revelation used to torment the wicked who are doomed to be cast into it. Prayer for the dead, especially as a mass, dates back to the early Church. Two martyr stories describe the martyrs as praying for the dead to improve the conditions of the dead in an intermediate state.
In the East, the intermediate state was described as light, freedom, and rest for the righteous and the opposite for the wicked. The intermediate state is sometimes described as the presence of God, which delights the believer and torments the unrepentant.
In the West, Augustine wrote that only those in communion with the church are aided by prayer. To the standard two-way division, he recognized separate states for the "not so good" and "not so bad" souls. He insisted that unbaptized babies were excluded from heaven. Gregory the Great confirmed Augustine's understanding that only the saved benefit from prayer, and he connected suffering after death with penance left unpaid in life.
The Venerable Bede and Saint Boniface both report visions of an afterlife with a four-way division, including pleasant and punishing abodes near heaven and hell to hold souls until judgment day.
In the 12th century, the medieval Catholic church defined purgatory, the intermediate state for the saved who have just punishment yet to suffer. The righteous were said to go direct to heaven, and the wicked direct to hell. All Souls' Day commemorates the souls in purgatory. The church sold indulgences to release the donors' departed loved ones from suffering in purgatory, or the donors themselves.
In the 16th century, the Protestant Reformation challenged purgatory. Martin Luther wrote that the soul slept unconsciously until the resurrection. John Calvin, in an ascerbic response to Luther, described the soul as resting in light. Protestants largely rejected a distinction in fates other than the difference between heaven and hell. They rejected distinctions of fate within heaven or hell and rejected purgatory almost entirely.