We know Christ by the Spirit 

You will often hear people say, “Oh, Jesus was a great teacher. Really, He and Lincoln and Plato have done a great deal for the world. If we wanted to solve all of our economic and social problems, all we would have to do is read the beatitudes of Jesus.” People who talk that way do not understand that Jesus is the Christ, the Son of God, the Redeemer of the world. For them, Jesus is just another man. Why do they not know Him? Because they do not have the Spirit. And why do they not have the Spirit?  Because they have not obeyed the law of God, however little or however much they knew of it. Our Lord said, “If you love me, keep my commandments.” Then the Holy Spirit will manifest Himself to us. The purpose of the Holy Spirit is that of an artist. He draws a picture of our Lord on the canvas. He makes him real to us so that we understand. Just as the artist stays outside of the canvas, so the Holy Spirit is staying outside of the Christ whom He reveals to us.