No man is fit to teach God’s truth until he is taught of God, and, to be taught, he must come into vital contact and sympathy with God. And so the power to witness implies a power to think rightly of God. Then we vividly see the real lost state of souls, and their awful need, and the wonders of grace and the possibility of salvation. This sense of reality of divine things no man has until the Spirit of God unveils his eyes and anoints them with His own eye-salve.
Arthur T. Pierson, The Divine Enterprise of Missions