Tertullian ca. 160-220St. Niphon then records, “As soon as the Judge pronounced that decison, at once, an enormous fiery river spilled over from the east and went rolling violently toward the west. It was broad like a big sea. When the sinners on the left saw it they were stunned and began to tremble, frightened in their despair. Nonetheless, the impartial Judge ordered everyone – just and unjust – to pass through the flaming river, so the fire could try them. Those at His right hand started first. They crossed and came out gleaming like solid gold. Their deeds did not burn, but instead proved to be brighter and clearer with the test; that is why they were filled with joy. After them, those at His left hand came to pass through the fire, so that their deeds might be tried. However, because they were evildoers, the flame began to envelop them and kept them in the middle of the river. Their deeds were burned like straw, whereas their bodies remained unharmed, to burn for endless ages along with the devil and the demons. No one was able to come out of that fiery river. The fire imprisoned all of them, because they deserved condemnation and punishment.” (The Lives of the Pillars of Orthodoxy pgs. 409-410)
Rev 19:11-12a Then I saw heaven opened, and behold, a white horse! The one sitting on it is called Faithful and True, and in righteousness he judges and makes war. His eyes are like a flame of fire, and on his head are many diadems…
The heavens opening signifies the appearance of the visible judge to come, just as here, when the curtains of the judges on the earth are drawn back the judgment and sentence come down upon those who are guilty. And the white horse is the future joy of the saints, upon which he is carried to judge the nations impartially, I think by His watchful, providential power throwing out flames of fire, which the righteous illuminate but do not burn, but the sinners burn and do not illumine. (Commentary on the Apocalypse)
St. Isaac of Syria ca. 7th cent.
That fire will flare up inside a man: on seeing the Cross, some will rejoice, while others will fall into despair, confusion, terror. In this way, men will immediately be separated. In the Gospel narrative, some stand to the right of the Judge, some to the left — their inner consciousness separated them. The very state of a man’s soul casts him to one side or the other, to the right or to the left.
The more consciously and persistently a man strives toward God in his life, the greater will be his joy when he hears the words: “Come unto Me, ye blessed”; and conversely, those same words will call forth the fire of horror and torment on those who did not want Him, who fled or fought or blasphemed Him during their life.
The Dread Judgment knows no witnesses or charge-sheets. Everything is recorded in men’s souls, and these records, these “books” are open. Everything becomes clear to all and to oneself, and the state of a man’s soul assigns him to the right or to the left.
Some go to joy, others to horror.
When the “books” are open, it will become clear to all that the roots of all vices are in man’s soul. Here is a drunkard, a fornicator; some may think that when the body dies the sin dies as well. No; the inclination was in the soul, and to the soul the sin was sweet.
And if [the soul] has not repented of that sin and has not become free of it, it will come to the Dread Judgment with the same desire for the sweetness of sin and will never satisfy its desire. In it will be the suffering of hatred and malice. This is the state of hell.
The “fiery Gehenna” is the inner fire; this is the flame of vice, the flame of weakness and malice; and
there will be [the] wailing and gnashing of teeth
