Scot Mcknight speaks about Rob's use of these two words:
Rob enters in this chapter into the judgment leads to restoration theme; consequences are for correction. This is a major point in his book. In this context he brings up the Greek word kolazo (it should be kolasis since the noun is used in Matthew 25), and Rob says something that must be flagged as unfair. He says kolazo “refers to the pruning and trimming of the branches of a plant so it can flourish” (91), and the noun is combined with aionion (he uses aion) and says this is an “aion of kolazo” or a “period of pruning.” Again, check BDAG [infliction of chastisement, punishment, transcendent retribution, punishment; under kolazo, the verb, penalize, punish ... finishing with "Aristotle's limitation of the term... to disciplinary action ... is not reflected in gener. usage"].
My point: it is simply disingenuous to say without qualification that it means pruning, and it is unfair to readers not to say that most — if not almost all — instances refer to a kind of retributive punishment and chastisement — there is very little emphasis in this word’s usage that suggests punish to improve and much more punish full stop. Here’s the big point: this is about Life and Kolasis/Punishment in The Age to Come. The Age to Come is everlasting.