St. Macarius the Great ca. 295-392

[S]ome speak of one kingdom and one hell. We, however, speak of many degrees and differences and measures, both in the kingdom and in hell itself. Just as the soul “ensouls” all the members and yet operates in the brain and still moves the feet below it, so also the Godhead contains all creatures, the heavenly and those under the abyss, and is everywhere being filled up in creation, even though it is most transcendent above creatures because it is infinite and beyond any comprehension. Therefore, this Godhead is concerned with men, and it providentially guides all things according to reason. And when some pray, not knowing what they seek, others fast, while others perservere in service, God being a just judge, gives the reward to each one according to the measure of his faith. For what things they do, they do out of fear of God. But not all these are sons or kings or heirs. In the world there are murderers, others are fornicators and others robbers. On the other hand, there are those who distribute their goods to the poor. For both of these groups the Lord has a concern and to those doing good He gives rest and a reward. For there are superior and inferior degrees. And in the very light itself and the glory there is a difference. And in hell itself and punishment there appear poisoners and robbers and others who have committed lesser sins. Those who say that there is only one kigdom and one hell and that there are not degrees, speak wrongly. (The Fifty Spiritual Homilies, Homily 40)

St. Gregory of Sinai ca. 1265-1346

Chastisements differ, as do the rewards of the righteous. Chastisements are inflicted in hell, in what Scripture describes as ‘a dark and gloomy land, a land of eternal darkness’ (Job 10:21-22 LXX), where sinners dwell before the judgment and whither they return after judgment is given. For can the phrases, ‘Let sinners be returned to hell’ (Ps. 9:17 LXX), and ‘death will rule over them’ (Ps. 49:14 LXX), refer to anything other than the final judgment visited upon sinners, and their eternal condemnation? (On Commandments and Doctrines, 33)

By ‘many dwelling-places’ (Jn. 14:2) the Saviour meant the differing stages of spiritual ascent and states of development in the other world; for although the Kingdom of Heaven is one, there are many different levels within it. That is to say, there is place for both heavenly and earthy men (cf. 1 Cor. 15:48) according to their virtue, their knowledge and the degree of deification that they have attained. ‘For there is one glory of the sun, and another glory of the moon, and another glory of the stars, for one star differs from another star in glory’ (1 Cor. 15:41); and yet all of them shine in a single divine firmament. (ibid., 44)