The Crow and the Fox

A Crow had stolen a cheese and carried it away to a high tree to eat it there in peace. A Fox saw it and meant to get it by a device. "Good Crow," said he, "what a lovely and shapely body you have! your color is more beautiful than that of many of the birds, and had you but a charming voice, surely you would hold the very first place." Thereupon she opened her mouth to sing, to show him he was wrong, when down fell the cheese. He picked it up and ran off with it saying: "To be sure you have a voice, Crow, but you haven’t any sense."

If you believe your enemy you will get punished for it.