Fallen human beings enter into joy only through the door of despair. Fullness can be had only through emptiness. That happens decisively at conversion, as we confess our hopelessly sinful predicament for the first time and collapse into the arms of Jesus, and then remains an ongoing rhythm throughout the Christian life. If you are not growing in Christ, one reason may be that you have drifted out of the salutary and healthy discipline of self-despair.
