‘Strive to enter through the narrow door; for many, I tell you, will try to enter and will not be able. When once the owner of the house has got up and shut the door, and you begin to stand outside and to knock at the door, saying, “Lord, open to us”, then in reply he will say to you, “I do not know where you come from.” Then you will begin to say, “We ate and drank with you, and you taught in our streets.” But he will say, “I do not know where you come from; go away from me, all you evildoers!” There will be weeping and gnashing of teeth when you see Abraham and Isaac and Jacob and all the prophets in the kingdom of God, and you yourselves thrown out. Then people will come from east and west, from north and south, and will eat in the kingdom of God.
It's not enough to sit back and enjoy the kingdom of God, as though "once saved always saved" were true. The kingdom demands a consistent and repeated effort of Christians.
And I don't see any indication of "success" at all. It's not even a matter of misunderstood success; we can't just say that we succeed by having a happy family rather than the false success of big house and a nice car. No, it looks as though it's the sincere intention of effort that is important in Jesus' message. Sincere intention of effort, and not just sincere intent; that's a necessary part of Christian being.