But we say that the fire sanctifies not flesh, but sinful souls; meaning not the all-devouring vulgar fire, but that of wisdom, which pervades the soul passing through the fire.Clement
Stromata Bk. 7 Ch. VI, Vol. 2

I asked her about the four colors which the beast had on his head. And she answered, and said to me, “Again you are inquisitive in regard to such matters.” “Yea, Lady, said I, “make known to me what they are.” “Listen,” said she: “the black is the world in which we dwell: but the fiery and bloody points out that the world must perish through blood and fire: but the golden part are you who have escaped from this world. For as gold is tested by fire, and thus becomes useful, so are you tested who dwell in it. Those, therefore, who continue steadfast, and are put through the fire, will be purified by means of it. For as gold casts away its dross, so also will ye cast away all sadness and straightness, and will be made pure so as to fit into the building of the tower. But the white part is the age that is to come, in which the elect of God will dwell, since those elected by God to eternal life will be spotless and pure. Wherefore cease not speaking these things into the ears of the saints. This then is the type of the great tribulation that is to come. If ye wish it, it will be nothing.Hermas
The Shepard Bk. 1 Pt. 2 Ch. III, Vol. 2

Those nations however, who did not of themselves raise up their eyes unto heaven, nor returned thanks to their Maker, nor wished to behold the light of truth, but who were like blind mice concealed in the depths of ignorance, the word justly reckons “as waste water from a sink, and as the turning-weight of a balance — in fact, as nothing;” (Isa_40:15) so far useful and serviceable to the just, as stubble conduces towards the growth of the wheat, and its straw, by means of combustion, serves for working gold. And therefore, when in the end the Church shall be suddenly caught up from this, it is said, “There shall be tribulation such as has not been since the beginning, neither shall be.” (Mat_24:21) For this is the last contest of the righteous, in which, when they overcome they are crowned with incorruption.Irenaeus
Against Heresies Bk. 5 Ch. XXIX, Vol. 1

Stand steadfast, therefore, ye who work righteousness, and doubt not, that your passage may be with the holy angels. Happy ye who endure the great tribulation that is coming on, and happy they who shall not deny their own life.Hermas
The Shepard Bk. 1 Pt. 1, Ch. II, Vol. 2

You have escaped from great tribulation on account of your faith, and because you did not doubt in the presence of such a beast. Go, therefore, and tell the elect of the Lord His mighty deeds, and say to them that this beast is a type of the great tribulation that is coming. If then ye prepare yourselves, and repent with all your heart, and turn to the Lord, it will be possible for you to escape it, if your heart be pure and spotless, and ye spend the rest of the days of your life in serving the Lord blamelessly. Cast your cares upon the Lord, and He will direct them. Trust the Lord, ye who doubt, for He is all-powerful, and can turn His anger away from you, and send scourges on the doubters. Woe to those who hear these words, and despise them: (1Th_5:20) better were it for them not to have been born.” (Mat_26:24)Hermas
The Shepard Bk. 1 Pt. 2 Ch. II, Vol. 2

If, because injustice is not from God, but from the devil, and persecution consists of injustice (for what more unjust than that the bishops of the true God, that all the followers of the truth, should be dealt with after the manner of the vilest criminals?), persecution therefore seems to proceed from the devil, by whom the injustice which constitutes persecution is perpetrated, we ought to know, as you have neither persecution without the injustice of the devil, nor the trial of faith without persecution, that the injustice necessary for the trial of faith does not give a warrant for persecution, but supplies an agency; that in reality, in reference to the trial of faith, which is the reason of persecution, the will of God goes first, but that as the instrument of persecution, which is the way of trial, the injustice of the devil follows.Tertullian
Tertullian -De Fuga Persecutione Ch. IX, Vol. IV

But we who hope for the Son of God are persecuted and trodden down by those unbelievers. For the wings of the vessels are the churches; and the sea is the world, in which the Church is set, like a ship tossed in the deep, but not destroyed; for she has with her the skilled Pilot, Christ. And she bears in her midst also the trophy (which is erected) over death; for she carries with her the cross of the Lord. For her prow is the east, and her stern is the west, and her hold is the south, and her tillers are the two Testaments; and the ropes that stretch around her are the love of Christ, which binds the Church; and the net which she bears with her is the laver of the regeneration1 which renews the believing, whence too are these glories. As the wind the Spirit from heaven is present, by whom those who believe are sealed: she has also anchors of iron accompanying her, viz., the holy commandments of Christ Himself, which are strong as iron. She has also mariners on the right and on the left, assessors2 like the holy angel, by whom the Church is always governed and defended. The ladder in her leading up to the sail yard is an emblem of the passion of Christ, which brings the faithful to the ascent of heaven. And the top-sails aloft upon the yard are the company of prophets, martyrs, and apostles, who have entered into their rest in the kingdom of Christ.Hippolytus
Fragments 2.2 Vol. 5