Μὴ γὰρ ἐπειδὴ πῦρ ἤκουσας, τοιοῦτον εἶναι νομίσῃς ἐκεῖνο τὸ πῦρ· τοῦτο μὲν γάρ, ὅπερ ἂν λάβῃ, κατέκαυσεν καὶ ἀπήλλαξεν, ἐκεῖνο δὲ τοὺς ἅπαξ κατασχεθέντας κάει διὰ παντὸς καὶ οὐδέποτε παύσεται. διὰ τοῦτο καὶ ἄσβεστον εἴρηται. καὶ γὰρ καὶ τοὺς ἡμαρτηκότας φθαρσίαν ἐνδύσασθαι δεῖ, οὐ πρὸς τιμὴν ἀλλ’ ὥστε διηνεκὲς ἐφόδιον τῆς τιμωρίας ἔχειν ἐκείνης· τοῦτο δὲ ὅσον ἐστὶ τὸ δεινόν, ὁ μὲν λόγος οὐκ ἂν ἰσχύσειεν παραστῆσαί ποτε, πὸ δὲ τῆς πείρας τῶν μικρῶν δυνατὸν βραχεῖάν τινα ἔννοιαν τῶν μεγάλων ἐκείνων λαβεῖν. εἰ γάρ ποτε ἐν βαλανείῳ γένοιο σφοδρότερον ἐκκεκαυμένῳ τοῦ δέοντος, τότε μοι τὸ τῆς γεέννης ἐννόησον πῦρ, καὶ εἴ ποτε πάλιν ὑπὸ πυρετοῦ καταφλεχθείης σφοδροῦ πρὸς ἐκείνην τὸν νοῦν τὴν φλόγα μετάστησον καὶ τότε δυνήσῃ διαστεῖλαι καλῶς. εἰ γὰρ βαλανεῖον καὶ πυρετὸς οὕτως ἡμᾶς θλίβει καὶ θορυβεῖ, ὅταν εἰς τὸν ποταμὸν τοῦ πυρὸς ἐμπέσωμεν ἐκεῖνον, τὸν ἑλκόμενον πρὸ τοῦ βήματος τοῦ φοβεροῦ, πῶς διακεισόμεθα; ἆρα βρύξομεν τοὺς ὀδόντας ὑπὸ τῶν πόνων καὶ τῶν ἀλγηδόνων τῶν ἀφορήτων ἐκείνων, ὁ δὲ ἐπαμύνων ἔσται οὐδείς, ἀλλ’ οἰμώξομεν μεγάλα σφοδρότερον ἐπιτιθεμένης ἡμῖν τῆς φλογός· ὀψόμεθα δὲ οὐδένα, πλὴν τῶν κολαζομένων σὺν ἡμῖν καὶ τῆς ἐρημίας τῆς πολλῆς. τί ἄν τις εἴποι τὰ ἀπὸ τοῦ σκότους δείματα, τὰ ταῖς ἡμετέραις ἐγγινόμενα ψυχαῖς; ὥσπερ γὰρ οὐκ ἔστιν ἀναλωτικὸν ἐκεῖνο τὸ πῦρ, οὕτως οὐδὲ φωτιστικόν· οὐδὲ γὰρ ἂν σκότος ἦν. τὸν τοίνυν τοιοῦτον ἀπὸ τούτου θόρυβον ἐγγινόμενον ἡμῖν καὶ τὸν τρόμον καὶ τὴν παράλυσιν καὶ τὴν ἔκστασιν τὴν πολλὴν ἐκεῖνος σαφῶς παραστῆσαι μόνος ὁ καιρὸς ἱκανός. πολλὰ γὰρ καὶ ποικίλα ἐκεῖ τὰ βασανιστήρια, καὶ νιφάδες πανταχόθεν κολάσεων ἐπάγονται τῇ ψυχῇ.
(John Chrysostom, Ad Theodorum Lapsum 1.10)
For when you hear of fire, do not suppose the fire in that world to be like this: for fire in this world burns up and makes away with anything which it takes hold of; but that fire is continually burning those who have once been seized by it, and never ceases: therefore also is it called unquenchable. For those also who have sinned must put on immortality, not for honour, but to have a constant supply of material for that punishment to work upon; and how terrible this is, speech could never depict, but from the experience of little things it is possible to form some slight notion of these great ones. For if you should ever be in a bath which has been heated more than it ought to be, think then, I pray you, on the fire of hell: or again if you are ever inflamed by some severe fever transfer your thoughts to that flame, and then you will be able clearly to discern the difference. For if a bath and a fever so afflict and distress us, what will our condition be when we have fallen into that river of fire which winds in front of the terrible judgment-seat. Then we shall gnash our teeth under the suffering of our labours and intolerable pains: but there will be no one to succour us: yea we shall groan mightily, as the flame is applied more severely to us, but we shall see no one save those who are being punished with us, and great desolation. And how should any one describe the terrors arising to our souls from the darkness? for just as that fire has no consuming power so neither has it any power of giving light: for otherwise there would not be darkness. The dismay produced in us then by this, and the trembling and the great astonishment can be sufficiently realized in that day only. For in that world many and various kinds of torment and torrents of punishment are poured in upon the soul from every side. (tr. W.R.W. Stephens)