2 Samuel 13:1-6

It happened afterwards that Absalom the son of David had a beautiful sister whose name was Tamar, and Amnon [her half brother] the son of David was in love with her. Amnon was so frustrated because of his [half-] sister Tamar that he made himself sick, for she was a virgin, and Amnon thought it impossible for him to do anything to her. But Amnon had a friend whose name was Jonadab the son of Shimeah, David’s brother; and Jonadab was a very shrewd (cunning) man. He said to Amnon, “Why are you, the king’s son, so depressed morning after morning? Will you not tell me?” And Amnon said to him, “I am in love with Tamar, my [half-] brother Absalom’s sister.” Jonadab said to him, “Go to bed and pretend you are sick; and when your father [David] comes to see you, say to him, ‘Just let my sister Tamar come and serve me food, and let her prepare it in my sight, so that I may see it and eat it from her hand.’ ” So Amnon lay down and pretended to be sick; and when the king came to see him, Amnon said to the king, “Please let my sister Tamar come and make me a couple of cakes in my sight, so that I may eat from her hand.”