Correct me if I am wrong - Purgatory is punishment for some sort of sin, is it not? It is about purifying.
Corinthians 3 has nothing to do with punishment. It merely says the work we do in building the church will be evaluated by God, and not everyone will have done a good job. Those who do a poor job will suffer the pangs of regret and sorrow for having built poorly - but there is no punishment in this passage. Nor is there any indication this is a prolonged period of time, or that those who built poorly will not be allowed in Heaven until they have suffered enough.
“Your statement implies you do not understand the Catholic doctrine of purgatory on its own terms.”
To be fair, bdeaner, very, very few people, including Roman Catholics, understand the Latin concept of purgatory. It is, by the way, another Latin “dogma” which may well prevent reunion of the the Pope with the other Patriarchs of The Church. The notion will receive no more support from Orthodox Christians than it did the last time Rome tried to jam it down Orthodoxy’s throat.
I think we understand very well what the doctrine is - just not the whole reason for it. If the blood of Jesus Christ cleanses us of ALL sin, it must mean our past, present and future sins, since we did not exist when he was crucified, are paid in full. Why do you believe there is something more that must be done to be sanctified? Somehow, our sufferings, no matter how long they last, can be placed alongside Christ's sufferings as equal? Can you not see the error in that thinking?
It boils down to the basics - are we saved by grace or works? Because it CANNOT be both.