The Encyclical Epistle Of The Church At Smyrna Concerning The Martyrdom Of The Holy Polycarp Disciple of John the apostle, 65-100-155 AD
And, looking to the grace of Christ, they despised all the torments of this world,
redeeming themselves from eternal punishment by [the suffering of] a single hour. For this reason the fire of their savage executioners appeared cool to them. For they kept before their view
escape from that fire which is eternal and never shall be quenched,
But Polycarp said, Thou threatenest me with fire which burneth for an hour, and after a little is extinguished, but art ignorant of
the fire of the coming judgment and of eternal punishment, reserved for the ungodly.
http://www.ccel.org/fathers2/ANF-01/anf01-13.htm#P911_166347
The Epistle Of Ignatius To The Ephesians Disciple of John the Apostle. 30-107 AD
Do not err, my brethren. Those that corrupt families
shall not inherit the kingdom of God. And if those that corrupt mere human families are condemned to death, how
much more shall those suffer everlasting punishment who endeavor to corrupt the Church of Christ, for which the Lord Jesus, the only-begotten Son of God, endured the cross, and submitted to death! Whosoever, being waxen fat, and become gross,
sets at nought His doctrine, shall go into hell.
http://www.ccel.org/fathers2/ANF-01/anf01-16.htm#P1093_206499
The Epistle Of Barnabas 100 AD
Chapter 20 The Way Of Darkness
But the way of darkness is crooked, and full of cursing; for it is the way of
eternal death with punishment, in which way are the things that destroy the soul, viz., idolatry, over-confidence, the arrogance of power, hypocrisy, double-heartedness, adultery, murder, rapine, haughtiness, transgression, deceit, malice, self-sufficiency, poisoning, magic, avarice, want of the fear of God.
http://www.ccel.org/fathers2/ANF-01/anf01-41.htm#P3130_520749
The First Apology Of Justin 110-165 AD
Chapter 1
[...]we say that the same thing will be done, but at the hand of Christ, and upon the wicked in the same bodies 297 united again to their spirits which are now to
undergo everlasting punishment; and not only, as Plato said, for a period of a thousand years.
Chapter 12
Christians Live As Under Gods Eye
we hold this view, that it is alike impossible for the wicked, the covetous, the conspirator, and for the virtuous, to escape the notice of God, and that
each man goes to everlasting punishment or salvation according to the value of his actions. For if all men knew this, no one would choose wickedness even for a little, knowing that
he goes to the everlasting punishment of fire;
we believe (or rather, indeed, are persuaded) that
every man will suffer punishment in eternal fire according to the merit of his deed, and will render account according to the power he has received from God,
Chapter 18
Proof Of Immortality And The Resurrection
For reflect upon the end of each of the preceding kings, how they died the death common to all, which, if it issued in insensibility, would be a god send to all the wicked. But since
sensation remains to all who have ever lived, and eternal punishment is laid up (i.e., for the wicked), see that ye neglect not to be convinced, and to hold as your belief, that these things are true.
Fear not them that kill you, and after that can do no more; but
fear Him who after death is able to cast both soul and body into hell. And hell is a place where those are to be punished who have lived wickedly, and who do not believe that those things which God has taught us by Christ will come to pass.
Chapter 22 And we have learned that
those only are deified who have lived near to God in holiness and virtue; and we believe that
those who live wickedly and do not repent are punished in everlasting fire.
Chapter 28
Gods Care For Men
For among us the prince of the wicked spirits is called the serpent, and Satan, and the devil, as you can learn by looking into our writings. And that
he would be sent into the fire with his host, and the men who follow him, and would be punished for an endless duration, Christ foretold.
Chapter 45
And if you also read these words in a hostile spirit, ye can do no more, as I said before, than kill us; which indeed does no harm to us, but to you and all who unjustly hate us, and
do not repent, brings eternal punishment by fire.
Chapter 52
He shall come from heaven with glory, accompanied by His angelic host, when also He shall raise the bodies of all men who have lived, and
shall clothe those of the worthy with immortality, and
shall send those of the wicked, endued with eternal sensibility, into everlasting fire with the wicked devils. And that these things also have been foretold as yet to be, we will prove. By Ezekiel the prophet it was said: Joint shall be joined to joint, and bone to bone, and flesh shall grow again; and every knee shall bow to the Lord, and every tongue shall confess Him. And
in what kind of sensation and punishment the wicked are to be, hear from what was said in like manner with reference to this; it is as follows: Their worm shall not rest, and their fire shall not be quenched; and
then shall they repent, when it profits them not.
http://www.ccel.org/fathers2/ANF-01/anf01-46.htm#P3593_620967
The Second Apology Of Justin Martyr For The Christians
For everywhere, whoever is corrected by father, or neighbor, or child, or friend, or brother, or husband, or wife, for a fault, for being hard to move, for loving pleasure and being hard to urge to what is right (except those who have been persuaded that
the unjust and intemperate shall be punished in eternal fire, but that the virtuous and those who lived like Christ shall dwell with God in a state that is free from suffering, we mean, those who have become Christians),
But when she came to the knowledge of the teachings of Christ she became sober-minded, and endeavored to persuade her husband likewise to be temperate, citing the teaching of Christ, and assuring him that
there shall be punishment in eternal fire inflicted upon those who do not live temperately and conformably to right reason.
But since God in the beginning made the race of angels and men with free-will,
they will justly suffer in eternal fire the punishment of whatever sins they have committed. and this is the nature of all that is made, to be capable of vice and virtue.
http://www.ccel.org/fathers2/ANF-01/anf01-47.htm#P3966_758753
Justin Dialogue with Trypho
Chapter 9
Eternal Punishment Not A Mere Threat
And that no one may say what is said by those who are deemed philosophers, that our assertions that
the wicked are punished in eternal fire are big words and bugbears, and that we wish men to live virtuously through fear, and not because such a life is good and pleasant; I will briefly reply to this, that if this be not so, God does not exist; or, if He exists, He cares not for men, and neither virtue nor vice is anything, and, as we said before, lawgivers unjustly punish those who transgress good commandments
Chapter 45
at the second coming of the Christ Himself, those who believe in Him and live acceptably, and be no more: when
some are sent to be punished unceasingly into judgment and condemnation of fire; but others shall exist in freedom from suffering, from corruption, and from grief, and in immortality.
Chapter 117
But these filthy garments, which have been put by you on all who have become Christians by the name of Jesus, God shows shall be taken away from us, when He shall raise all men from the dead, and
appoint some to be incorruptible, immortal, and free from sorrow in the everlasting and imperishable kingdom; but
shall send others away to the everlasting punishment of fire.
Chapter 130
But we will not receive it of all your nation; since we know from Isaiah that the members of
those who have transgressed shall be consumed by the worm and unquenchable fire, remaining immortal; so that they become a spectacle to all flesh.
http://www.ccel.org/fathers2/ANF-01/anf01-48.htm#P4043_787325
Irenaeus Against Heresies Book 4, Disciple of Polycarp a disciple of John, 120-202 AD
Chapter 27 The Future Judgment By Christ. Communion With And Separation From The Divine Being. The Eternal Punishment Of Unbelievers.
Those, therefore, who cast away by apostasy these forementioned things, being in fact destitute of all good, do experience every kind of punishment. God, however, does not punish them immediately of Himself, but
that punishment falls upon them because they are destitute of all that is good.
Now, good things are eternal and without end with God, and
therefore the loss of these is also eternal and never-ending.
God showed Himself not well pleased in many instances towards those who sinned, so also in the latter,
many are called, but few are chosen. As then the unrighteous, the idolaters, and fornicators perished, so also is it now: for both the Lord declares, that
such persons are sent into eternal fire; and the apostle says, Know ye not that
the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, not effeminate, nor abusers of themselves with mankind, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.
Chapter 28
1. Inasmuch, then, as in both Testaments there is the same righteousness of God [displayed] when God takes vengeance, in the one case indeed typically, temporarily, and more moderately; but
in the other, really, enduringly, and more rigidly: for the fire is eternal, and the wrath of God which shall be revealed from heaven from the face of our Lord (as David
also says, But the face of the Lord is against them that do evil, to cut off the remembrance of them from the earth), entails a heavier punishment on those who incur it, the elders pointed out that those men are devoid of sense, who, [arguing] from what happened to those who formerly did not obey God, do
endeavor to bring in another Father, setting over against [these punishments] what great things the Lord had done at His coming to save those who received Him, taking compassion upon them; while they keep silence with regard to His judgment; and all those things which shall come upon such as have heard His words, but done them not, and that it were better for them if they had not been born, and that it shall be more tolerable for Sodom and Gomorrha in the judgment than for that city which did not receive the word of His disciples.
Chapter 28
when we are directed not merely to abstain from evil actions, but even from evil thoughts, and from idle words, and empty talk, and scurrilous language: thus also
the punishment of those who do not believe the Word of God, and despise His advent, and are turned away backwards, is increased; being not merely temporal, but rendered also eternal. For to whomsoever the Lord shall say,
Depart from me, ye cursed, into everlasting fire, these shall be damned for ever;
Chapter 39
For as in the case of this temporal light, those who shun it do deliver themselves over to darkness, so that they do themselves become the cause to themselves that they are destitute of light, and do inhabit darkness; and, as I have already observed, the light is not the cause of such an [unhappy] condition of existence to them; so those who fly from the eternal light of God, which contains in itself all good things,
are themselves the cause to themselves of their inhabiting eternal darkness, destitute of all good things, having become to themselves the cause of [their consignment to] an abode of that nature.
Chapter 52 He shall come from heaven with glory, accompanied by His angelic host, when also He shall raise the bodies of all men who have lived, and shall clothe those of the worthy with immortality, and
shall send those of the wicked, endued with eternal sensibility, into everlasting fire with the wicked devils.
http://www.ccel.org/fathers2/ANF-01/anf01-62.htm#P7979_2198226
Irenaeus Against Heresies Book 5
The breath, then, is temporal, but the Spirit eternal.
Let those persons, therefore, who blaspheme the Creator, either by openly expressed words, such as the disciples of Marcion, or by a perversion of the sense [of Scripture], as those of Valentinus and all the Gnostics falsely so called, be recognized as agents of Satan by all those who worship God; through whose agency Satan now, and not before, has been seen to speak against
God, even Him who has prepared eternal fire for every kind of apostasy.
Chapter 26 Truly has Justin remarked: That before the Lords appearance Satan never dared to blaspheme God, inasmuch as he did not yet know his own sentence, because it was contained in parables and allegories; but that after the Lords appearance, when he had clearly ascertained from the words of Christ and His apostles
that eternal fire has been prepared for him as he apostatized from God of his own free-will, and likewise for all who unrepentant continue in the apostasy, he now blasphemes, by means of such men, the Lord who brings judgment [upon him] as being already condemned, and imputes the guilt of his apostasy to his Maker, not to his own voluntary disposition.
Chapter 27 The Future Judgment By Christ. Communion With And Separation From The Divine Being. The Eternal Punishment Of Unbelievers
And on this account He says, that those upon the right hand are called into the kingdom of heaven, but that
those on the left He will send into eternal fire for they have deprived themselves of all good.
http://www.ccel.org/fathers2/ANF-01/anf01-63.htm#P8900_2545577