[Father Wacław Hryniewicz (Roman Catholic priest, Theologian, a member of the Missionary Oblates of Mary Immaculate, professor of theology, and director of the Ecumenical Institute at the John Paul II Catholic University of Lublin Poland)]
Hope dares to trust that God will not remain completely helpless in the face of human freedom, that he will finally be able to draw it towards himself, purify and transform it thanks to his patient and boundless love. This can be achieved through suffering and torment which in human language could be termed endless, aeonic, i.e.lasting for centuries, because of its quality and intensity, as is suggested by the Greek word aiōnios. A great thinker of the Early Church, Origen, one of the propagators of hope for universal salvation, was well aware of this. He pointed many times to the ambiguity of the term aiōnios, used in the Bible to denote either eternity or only long duration. He regarded the punishment, termed in the Bible as ‘eternal’, as the sign of God’s mercy, as a cure designed to bring about improvement and conversion. God will finally manage to soften and overcome any resistance and revolt of his creatures without violating their free will.
Source: Hryniewicz, Wacław. The Challenge of Our Hope: History and Eschatology. Theo-Logos, 2007, p. 81
[From Marvin Vincent, of "Vincent's Word Studies"]
Aion, transliterated aeon, is a period of longer or shorter duration, having a beginning and an end, and complete in itself. Aristotle (peri ouranou, i. 9,15) says: "The period which includes the whole time of one's life is called the aeon of each one." Hence it often means the life of a man, as in Homer, where one's life (aion) is said to leave him or to consume away (Iliad v. 685; Odyssey v. 160). It is not, however, limited to human life; it signifies any period in the course of events, as the period or age before Christ; the period of the millennium; the mythological period before the beginnings of history.The adjective aionios in like manner carries the idea of time. Neither the noun nor the adjective, in themselves, carry the sense of endless or everlasting. They may acquire that sense by their connotation, as, on the other hand, aidios, which means everlasting, has its meaning limited to a given point of time in Jude 6. Aionios means enduring through or pertaining to a period of time. Both the noun and the adjective are applied to limited periods.Words which are habitually applied to things temporal or material cannot carry in themselves the sense of endlessness...
https://web.archive.org/web/20180521042920/http://www.auburn.edu/~allenkc/vincent.html
[Olnmpiodorus the Younger, a 6th century Neo-Platonist]
Do not suppose that the soul is punished for endless eons (apeirou aionas) in Tartarus. Very properly, the soul is not punished to gratify the revenge of the divinity, but for the sake of healing. But we say that the soul is punished for an aionion period (aionios) calling its life and its allotted period of punishment, its aeon.
Source: Olnmpiodorus the Younger (AD 550)
Ambrosius Autpertus (an 8th century priest, who wrote commentaries on Holy Scripture and on the lives of the saints, and is venerated as a saint within the Roman Catholic Church.)
Rev 20:10 “And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are: and they shall be tormented day and night for ever and ever (Latin saecula saeculorum)." But when it says, "they shall be tormented day and night for ever and ever (Latin: saecula saeculorum)," it is not to be taken in such a way that no sentence of God’s mercy is left at all: but because very long times (Latin: saecula saeculorum) are appointed for punishments, which human frailty cannot measure. It can happen that even the evil spirits themselves, who are now obstinate in their wickedness, after very long times (Latin: saecula saeculorum) are freed by God’s mercy, when they put off the nature which they corrupted, and are reformed to that for which they were created. But if this is so, it does not detract from divine justice, because they will have paid for a very long time what they deserved.
Source: Ambrosius Autpertus--Commentary on the Apocalypse (c. 784 AD), Book 10, ch. 36. Patrologia Latina 89:1391.