In the pages of this book, we will try to present the Sermon on the Mount from the particular perspective of the “notion” of the mature—that is, perfect—person in Jesus’ mind. Our Lord has outlined the main features of human maturity. It is an ideal that Jesus makes us look at with eyes full of hope and a spirit willing to conquer. This is what we must strive to become. If people were to know and to put into practice the directives of Our Lord, we can be sure that we would not have so many problems of emotional or intellectual immaturity, and that the psychic conflicts that this annoying modern life has accustomed us—and desensitized us—to would be greatly lessened. Jesus speaks with authority because He has it. That authority—to be understood in the topic that we have studied here—is His because He Himself is the mature Man par excellence. The image that He transmits to us is a perfect image of Himself.