2 Samuel 13:3-5

3Now Amnon had a friend named Jonadab, the son of David’s brother Shimeah. Jonadab was a very crafty man.

4He asked Amnon, “Why are you, the king’s son, so depressed every morning? Can’t you tell me?” So Amnon said to him, “I’m in love with Tamar the sister of my brother Absalom.”

5Jonadab replied to him, “Lie down on your bed and pretend to be sick. When your father comes in to see you, say to him, ‘Please let my sister Tamar come in so she can fix some food for me. Let her prepare the food in my sight so I can watch. Then I will eat from her hand.’”