All of us who try enough and persevere in doing good and avoiding all kinds of evil, believers and non-believers alike, will go through purgatory to be purified upon entering heaven, with exceptions for those who truly lived heroic virtues or became martyrs for Christ and his Church.
The existence of purgatory does not depend on man’s reason. It is God’s manifestation of his divine mercy. As Saint Teresa prays: “My God, what soul will be pure enough to enter into Heaven without passing through the vengeful flames?”
Many canonized saints have shared about their own account and visions about Purgatory. Sharing here two anecdotes from the writings of Saint John Vianney the “Cure of Ars” and patron of diocesan priests.
Story of Saint Peter Damien’s Sister
St. Peter Damien tells that his sister remained several years in Purgatory because she had listened to an evil song with some little pleasure. It is told that two religious promised each other that the first to die would come to tell the survivor in what state he was. God permitted the one who died first to appear to his friend. He told him that he was remaining fifteen years in Purgatory for having liked to have his own way too much. And as his friend was complimenting him on remaining there for so short a time, the dead man replied: “I would have much preferred to be flayed alive for ten thousand years continuously, for that suffering could not even be compared with what I am suffering in the flames.” (from the Book “The Sermons of The Cure of Ars”, TAN Books 2013, Page 174)
Story of Saint Severinus
The most astonishing thing was that there were actually saints there, even ones who were canonized, who were passing through Purgatory. St. Severinus, Archbishop of Cologne, appeared to one of his friends a long time after his death and told him that he had been in Purgatory for having deferred to the evening the prayers he should have said in the morning. Oh! What years of Purgatory will there be for those Christians who have no difficulty at all in deferring their prayers to another time on the excuse of having to do some pressing work! If we really desired the happiness of possessing God, we should avoid the little faults as well as the big ones, since separation from God is so frightful a torment to all these poor souls! (from the Book “The Sermons of The Cure of Ars”, TAN Books 2013, Page 175)