The following quotes are from the first apology of Justin written A.D. 155-157
And Plato, in like manner, used to say that Rhadamanthus and Minos would punish the wicked who came before them; and we say that the same thing will be done, but at the hand of Christ, and upon the wicked in the same bodies 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. ~Chap. VIII
[I]t 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. ~Chap. XII
But if you pay no regard to our prayers and frank explanations, we shall suffer no loss, since 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, as Christ intimated when He said, “To whom God has given more, of him shall more be required.” ~Chap. XVII
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 godsend 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. ~Chap. XVIII
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. ~Chap. XIX
[W]e affirm that the souls of the wicked, being endowed with sensation even after death, are punished, and that those of the good being delivered from punishment spend a blessed existence. ~Chap. XX
[W]icked devils perpetrated these things. 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. ~Chap. XXI
And that he [the devil] 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. ~Chap. XXVIII
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. ~Chap. XLV
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. ~Chap. LII
The following quotes are from the second apology of Justin written A.D. 161-165
[T]he 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. ~Chap. I
[C]iting 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. ~Chap. II
But since God in the beginning made the race of angels and men with free-will, they will justly suffer in eternal fire the punishement of whatever sins they have committed. ~Chap. VII
And they [devils], having been shut up in eternal fire, shall suffer their just punishment and penalty. For if they are even now overthrown by men through the name of Jesus Christ, this is an intimation of the punishment in eternal fire which is to be inflicted on themselves and those who serve them. For thus did both all the prophets foretell, and our own teacher Jesus teach. ~Chap. VIII