St. Isaac the Syrian ca. 7th cent.
In the future separation there will be no middle realm between the state that is completely on high and the state that is absolutely below. A person will either belong entirely to those who dwell on high, or entirely to those below; but within both the one state and the other are diverse degrees of recompense. If this is true, which it most certainly is, what is more senseless and more foolish than those who say that ‘It is enough for me to escape Gehenna, I do not seek to enter the kingdom!’ For to escape Gehenna means precisely to enter the kingdom, even as falling away from the kingdom is entering Gehenna. Scripture has taught us nothing about the existence of three realms, but ‘When the Son of God will come in His glory, He shall set the sheep on His right hand, but the goats on the left.’ (Mat. 25:31-33)…How have you not understood by these things that falling short of the order on high is, in fact, the Gehenna of torment? (The Spiritual World of Isaac the Syrian by Hilarion Alfeyev, pp. 278-279)
