Before treating of the force and usage of this adjective, it is well to examine briefly into αἰών, from which it is formed. The earliest application of the substantive in Greek writers (as Homer, Hesiod, Pindar, the tragic poets, and Herodotus) is in the sense of a man's life, or lifetime. In the later history of the language (not to speak of its medical application to "the spinal marrow ") it denoted a long period of time (Aeschin. Axioch. 17), while the philosophers employed it in contradistinction to χρόνος to express the duration, χρόνος of eternal and unchangeable objects, χρόνος of such as are transient and corporeal. Hence αἰών was used in the ancient philosophy as = the infinite and immutable eternity of God, and by an obvious metonymy = God himself, and subordinate spiritual beings who were supposed to proceed from Him, the term of duration being also extended to those invisible agents or entities themselves. Thus Philo Judaeus says, ἐν αἰῶνι δὲ οὔτε παρελήλυθεν οὐδὲν οὔτε μέλλει ἀλλὰ μόνον ὐφέστηχε. This is important, as showing that in Hellenistic Greek authors of the same age as those of the New Testament the word was used properly and specifically to set forth eternity. " In eternity nothing is past or future, but only subsists." Equally plain is its application to the invisible beings or aeons of Oriental philosophy, as may be seen from the following extract, cited by Mosheim, from Arrian:-οὐ γὰρ εἰμὶ Λἰὼν ἀλλ’ἄνθρωπος, μέρος τῶν πάντων ὡς ὤρα ἡμέρας, ἐνστῆναι με δεῖ ὡς τὴν ὤραν χαὶ παρελθεῖν ὡς ὤραν. Excluding the imaginary- personal force, nothing can be clearer than its use in the time and language of the New Testament inspired writers to represent what is immutable and eternal. Aristotle, I may add, derives it from αἰὲν ὤν(De Coelo,1: 11).
I conclude, then, that while αἰών may be so used as to express the continuous existence of a thing which from its nature does not last forever (as human life, an unbroken age or dispensation, or the general course of this world), its proper sense, taken by itself, is to express eternity. And the same thing is true of αἰώνιος. It is used in certain special connections, as in Rom. 16:2525Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, (Romans 16:25); 2 Tim. 1:99Who hath saved us, and called us with an holy calling, not according to our works, but according to his own purpose and grace, which was given us in Christ Jesus before the world began, (2 Timothy 1:9); and Titus 1:22In hope of eternal life, which God, that cannot lie, promised before the world began; (Titus 1:2), where χρόνοι modifies its force, and gives a relative rather than an absolute sense; but its natural meaning, unless positively restricted, is eternal in contrast with temporary. It occurs seventy-one- times in the received text of the New Testament, the examination of which need leave no doubt on the believer's mind. Donnegan gives Philem. 1:1515For perhaps he therefore departed for a season, that thou shouldest receive him for ever; (Philemon 15) as exceptional; but he is, in my opinion, mistaken.