Maybe purgatory makes sense if sin is like routine dirt that comes with perspiration, dust, food, like going through the motions in worship:
Let’s imagine you’re dead…. But you were busy….
So we, sinful creatures all, step out of this life into eternity—and we know, more clearly than we have never known anything, that we are not worthy to be in the presence of the Almighty God. In life, we may have casually popped the Eucharist onto our tongue, drunk of the Precious Blood, then gone back to our pews to idly watch the others return to their seats, ogling the cute boys or checking out the fashion faux pax, hardly pausing to ponder the great impossibility, the unimaginable truth, that God has given Himself to us, in the flimsy gift wrap of bread and wine. Wholly. Fully.
We have ignored Him, too, when we have not bothered to pray; when we have gossiped about our neighbors; when we have shirked our responsibilities in the workplace, when we have allowed anger to govern our relationships or our driving, when we have cheated on our diets or (yikes!) cheated on our spouses.
We are earthen vessels, all of us. And we know instinctively that we cannot face the great and mighty God in our current condition. True, we have been redeemed by the Blood of Christ, and His sacrifice has made it possible for us to be with Him for all eternity. First, though, we need to wash up—get ready for the party, for the great receiving line.
That’s what Purgatory is. It’s the washroom, the hot shower, where we become like Him.
Just imagine being in a hot shower for a millennium.
But if sin is like murder or deceit, something that takes you from innocent to guilty, maybe even gets you kicked out of the Garden of Eden and forces God to position angels with fiery swords to prevent you from going back, maybe you need something stronger to remove the stain of guilt.
Something like the active obedience of Christ? No clean without it.