At the very beginning of the Gospels, Jesus calls us to a radical new way of life, saying: "This is the time of fulfillment. The kingdom of God is at hand. Repent, and believe in the gospel" (Mk 1:15). The word "repent" in Greek is metanoia -- but the original Greek word means much more than just repentance. It means to change, to turn, to think differently. Metanoia is not a one-time event but a process, and as Christians we are called...