David Wilkerson emphasizes that as believers, we are called to be living manifestations of Jesus Christ, making His truth known to the world. He explains that we are like letters from God, written not with ink but by the Spirit, reflecting the nature of Christ in our lives. The Holy Spirit works within us to shape our character and image to be more like Jesus, enabling us to impact others profoundly. By spending time in His presence, we become powerful testimonies of His love and truth, compelling others to seek Him. Ultimately, our lives should shine forth the essence of Christ, drawing others to Him.