Prayer: Dietrich Bonhoeffer, The Cost of Discipleship

If there is no element of asceticism in our lives, if we give free rein to the desires of the flesh (taking care of course to keep within the limits of what seems permissible to the world), we shall find it hard to train for the service of Christ. When the flesh is satisfied it is hard to pray with cheerfulness or to devote oneself to a life of service which calls for much self-renunciation.