Some quotes from early church history:
Sibylline Oracles (80-195 AD)
And God, immortal and omnipotent, will grant another gift to these pious
persons: when they will ask him, he will grant them to save the human beings
from the fierce fire, and from the otherworldly [αἰώνιος] gnashing of teeth, and
will do so after pulling them out of the unquenchable flame and removing
them [ἀπὸ φλογὸς ἀκαμάτοιο ἄλοσ’ ἀποστήσας], destining them, for the sake
of his own elect, to the other life, that of the world to come, for immortals
[ζωὴν ἑτέραν καὶ αἰώνιον ἀθανάτοισιν], in the Elysian Fields, where there are the
long waves of the Acherusian Lake, imperishable, which has a deep bed.
(2,330–338)
Apocalypse of Peter (c. 100-150 AD)
Then I will grant to my called and elect ones whomsoever they request from me, out of the punishment. And I will give them [i.e. those for whom the elect pray] a fine baptism in salvation from the Acherousian Lake (which is, they say, in the Elysian field), a portion of righteousness with my holy ones (ApPet 14:1, translating the text as corrected by M. R. James and confirmed by SibOr 2:330-338).
Bardaisan of Edessa (154–222 AD)
“But whenever God likes, everything can be, with no obstacle at all. In fact,
there is nothing that can impede that great and holy will. For, even those
who are convinced to resist God, do not resist by their force, but they are
in evil and error, and this can be only for a short time, because God is kind
and gentle, and allows all natures to remain in the state in which they are,
and to govern themselves by their own will, but at the same time they are
conditioned by the things that are done and the plans that have been conceived
[sc. by God] in order to help them. For this order and this government that have
been given [sc. by God], and the association of one with another, damps the
natures’ force, so that they cannot be either completely harmful or completely
harmed, as they were harmful and harmed before the creation of the world.
And there will come a time when even this capacity for harm that remains in
them will be brought to an end by the instruction that will obtain in a different
arrangement of things: and, once that new world will be constituted, all evil
movements will cease, all rebellions will come to an end, and the fools will be
persuaded, and the lacks will be filled, and there will be safety and peace, as a
gift of the Lord of all natures.” (Laws of Countries, 608–611 Nau)
Clement of Alexandria (150-215)
And not only for our sins,’-that is for those of the faithful,-is the Lord the propitiator, does he say, ‘but also for the whole world.’ He, indeed, saves all; but some He saves, converting them by punishments; others, however, who follow voluntarily He saves with dignity of honour; so ‘that every knee should bow to Him, of things in heaven, and things on earth, and things under the earth;’ that is, angels, men, and souls that before His advent have departed from this temporal life." (Fragments, 1:3, c. 2, v. 2)
Origen (c. 184 - c. 253) "So then, when the end has been restored to the beginning, and the termination of things compared with their commencement, that condition of things will be re-established in which rational nature was placed, when it had no need to eat of the tree of the knowledge of good and evil; so that when all feeling of wickedness has been removed, and the individual has been purified and cleansed, He who alone is the one good God becomes to him ‘all,’ and that not in the case of a few individuals, or of a considerable number, but He Himself is ‘all in all.’ And when death shall no longer anywhere exist, nor the sting of death, nor any evil at all, then verily God will be ‘all in all’— De Prinicipiis 3.6.3
Didymus the Blind of Alexandria (310/13 ca.–395/8 AD)
This is said about rational creatures [τῶν λογικῶν]. Since, among all of them, there are also some who have become wicked, know how these will have a restoration [κατάστασιν] once they have arrived in the hands of the Son, obviously after rejecting the evilness [κακίαν] that they had, and assuming virtue [ἀρετήν]. For one should not pay attention to those who propound sophisms, claiming that only those rational beings who have sanctity [ἁγιότητα] are called. [In Comm. in Io., fr. 2]
It is impossible that wood, grass, and straw disappear in such a way as not to exist any more, but sinners will disappear insofar as they are grass and so on. Indeed, this fire of the corrective punishment is not active against the substance, but against habits and qualities [sc. bad habits and qualities]. For this fire consumes, not creatures, but certain conditions and certain habits. [Comm. in Ps. 20–21 col. 21,15]
“Gregory of Nyssa (A.D. 330-394)
A certain deception was indeed practised upon the Evil one, by concealing the Divine nature within the human; but for the latter, as himself a deceiver, it was only a just recompense that he should be deceived himself: the great adversary must himself at last find that what has been done is just and salutary, when he also shall experience the benefit of the Incarnation. He, as well as humanity, will be purged.” (The Great Catechism, 26, newadvent.org/fathers/2908.htm)”
"the originator of evil himself will be healed” (Catechetical Orations 26. The Catechetical Oration of Gregory of Nyssa. Edited by James H. Srawley. Cambridge, 1903, p. 101).
‘For it is evident that God will, in truth, be ‘in all’ then when there shall be no evil seen in anything. … When every created being is at harmony with itself and every tongue shall confess that Jesus Christ is Lord; when every creature shall have been made one body, then shall the body of Christ be subject to the Father. … Now the body of Christ, as I have said often before, is the whole of humanity’ (Orat. in I Cor. xv.28).