William Barclay, author of The Daily Study Bible Series, wrote: “[ Aionios] means more than everlasting, for Plato—who may have invented the word—plainly says that a thing may be everlasting and still not be aionios . . . aionios cannot be used properly of anyone but God; it is the word uniquely, as Plato saw it, of God. Eternal punishment is then literally that kind of remedial punishment which it befits God to give and which only God can give.”
According to David Hill, aionios sometimes suggests “quality of being, almost meaning ‘divine’ rather than enduring.” When aionios modifies words like “life,” “glory,” “righteousness,” “salvation,” “wrath,” and “punishment,” could it not be that the writers are simply speaking of these things as coming from God, and being manifestations of His character or attributes, which are eternal?