The Enchiridion by St. Augustine
Chapter 111.--After the Resurrection There Shall Be Two Distinct Kingdoms, One of Eternal Happiness, the Other of Eternal Misery.
After the resurrection, however, when the final, universal judgment has been completed, there shall be two kingdoms, each with its own distinct boundaries, the one Christ's, the other the devil's; the one consisting of the good, the other of the bad, -- both, however, consisting of angels and men. The former shall have no will, the latter no power, to sin, and neither shall have any power to choose death; but the former shall live truly and happily in eternal life, the latter shall drag a miserable existence in eternal death without the power of dying; for the life and the death shall both be without end. But among the former there shall be degrees of happiness, one being more pre-eminently happy than another; and among the latter there shall be degrees of misery, one being more endurably miserable than another.