The greatest task in this struggle is not to regard these thoughts, not to explore them, not to pursue the matters suggested, but despise them like the hissing of a goose and pass them by. The person that has learned to do this will conquer; whoever has not learned it will be conquered. For to muse upon these thoughts and debate with them means to stimulate them and make them stronger. Take the people of Israel as an example: they overcame the serpents, not by looking at them and wrestling with them, but by turning their eyes away from them and looking in a different direction, namely, at the brazen serpent, and they conquered. In this struggle that is the right and sure way of winning the victory. A person afflicted with such thoughts said to a certain wise man: What evil thoughts come into my mind! He received the answer: Well, let them pass out again. That remark taught the person a fine lesson. Another answered the same question thus: You cannot keep the birds from flying over your head, but you can keep them from building their nests in your hair. Accordingly, you will do the correct thing when you are merry and engage in some pleasant pastime with some one, and not scruple afterwards over having done so. For God is not pleased with sadness, for which there is no reason. The sorrow over our sins is brief and at the same time is made pleasant to us by the promise of grace and the forgiveness of sins. But the other sorrow is of the devil and without promise; it is sheer worry over useless and impossible things which concern God. I shall have more to say to you when I return. Meanwhile give my greetings to your brother; I began writing to him, but the messenger who is to take this letter along is in a hurry. I shall write to him later, also to Schneidewein and others. I commend your pupil to you. May the Spirit of Christ comfort and gladden your heart! Amen.' (21a, 1487 ff.)