2 Samuel 13:3-5

3Now Amnon had an adviser named Jonadab son of Shimeah, David’s brother. Jonadab was a very shrewd man.

4He asked Amnon, “Why do you, the king’s son, look so haggard morning after morning? Won’t you tell me?” Amnon said to him, “I’m in love with Tamar, my brother Absalom’s sister.”

5“Go to bed and pretend to be ill,” Jonadab said. “When your father comes to see you, say to him, ‘I would like my sister Tamar to come and give me something to eat. Let her prepare the food in my sight so I may watch her and then eat it from her hand.’ ”