"Purgatory is not, as Tertullian thought, some kind of supra-worldly concentration camp where man is forced to undergo punishment in a more or less arbitrary fashion. Rather it is the inwardly necessary process of transformation in which a person becomes capable of Christ, capable of God, and thus capable of unity with the whole communion of saints".
Joseph Ratzinger, Eschatology: Death and Eternal Life, CUA Press, p. 230.
