I think the precondition is simple: acknowledge sin, accept forgiveness, take some lumps (I do believe in Purgatory), and go on to Heaven.
The problem with Hell is that eternal damnation seems too severe. After all, our sins are finite, and the punishment seems disproportional. On the other hand, if we do not care to change, we are not fit to stand in God's presence, even after punishment. It seems to me that we must accept judgment, and therefore some amount of penitential suffering, in order to qualify for Heaven. Those who will not embrace penance may very well linger in Hell. Even then, I wonder if we have a great deal of time to confess our sins, even after death, and if we get to move into Limbo once we have been punished, not standing in God's presence, but not experiencing torment....... |