"Do not be anxious about my health. To be sure, I do not know what is the matter. But because I feel that I am not suffering from any natural disease, I bear my condition more easily and scoff at the messenger of Satan who buffets my flesh. If I cannot read and write, I can still meditate and pray and in this way contend with the devil, and I can also sleep, loaf, play and sing."
Martin Luther, writing to Philip Melanchthon, July 31, 1530, quoted in Theodore G. Tappert, editor, Luther: Letters of Spiritual Counsel, pages 154-155.