What does it mean that the violent take the kingdom of heaven by force?

We have this very peculiar verse in the Gospels where Christ says the kingdom of heaven is taken by force and violent men seek to take it. And I'm reminded of a friend of mine, a fellow priest, who said when he was Protestant he could never make sense of this. In fact, he went to the pastors of his church and said, what does this verse mean? And he said nobody could answer it. What does this mean, the violent take the kingdom of heaven by force? But since we have the treasury of the saints and their commentaries on the gospel, especially Blessed Theophylact, we know that the violent, in the words of Christ, are those who are willing to do violence to themselves. This is the self-denial that is required in order to cultivate the kingdom of heaven. A man has to be set against himself. In fact, if we look all the way back to the Garden of Eden, the whole problem for Adam wasn't just the sin. In fact, the saints tell us that it wasn't his sin that was the ultimate problem, it was the lack of repentance.