Book excerpt: The New York Times bestselling author of The Prodigal Prophet uncovers the essential message of Jesus, locked inside his most familiar parable. Newsweek called renowned minister Timothy Keller "a C.S. Lewis for the twenty-first century" in a feature on his first book, The Reason for God. In that book, he offered a rational explanation of why we should believe in God. Now, in The Prodigal God, Keller takes his trademark intellectual approach to understanding Christianity and uses the parable of the prodigal son to reveal an unexpected message of hope and salvation. Within that parable Jesus reveals God's prodigal grace toward both the irreligious and the moralistic. This book will challenge both the devout and skeptics to see Christianity in a whole new way.