The gracious call of Jesus now becomes a stern command: Do this! Give up that! Leave the ship and come to me! When a man says he cannot obey the call of Jesus because he believes, or because he does not believe, Jesus says: “First obey, perform the external work, renounce your attachments, give up the obstacles which separate you from the will of God. Do not say you have not got faith. You will not have it so long as you persist in disobedience and refuse to take the first step. Neither must you say that you have faith, and therefore there is no need for you to take the first step.
