Original: In Roman Catholicism, those who die in a state of grace, i.e. without any mortal sin separating them from God, but are still imperfectly purified from the effects of sin, undergo purification through the intermediate state of purgatory to achieve the holiness necessary for entrance into God's presence.
Simplified: For example, in Roman Catholicism, those who die in a state of grace, go into purgatory.