" Now, the English word “age” here is the word aion in New Testament Greek. Aion has multiple meanings—one we’ll look at here, and another we’ll explore later. One meaning of aion refers to a period of time, as in “The spirit of the age” or “They were gone for ages.” When we use the word “age” like this, we are referring less to a precise measurement of time, like an hour or a day or a year, and more to a period or era of time. This is crucial to our understanding of the word aion, because it doesn’t mean “forever” as we think of forever. When we say “forever,” what we are generally referring to is something that will go on, year after 365-day year, never ceasing in the endless unfolding of segmented, measurable units of time, like a clock that never stops ticking. That’s not this word. The first meaning of this word aion refers to a period of time with a beginning and an end. "

― Rob Bell , Love Wins: A Book About Heaven, Hell, and the Fate of Every Person Who Ever Lived