In the course of time, Amnon1 son of David fell in love with Tamar,2 the beautiful sister of Absalom3 son of David.
References for 2 Samuel 13:1
Amnon became frustrated to the point of illness on account of his sister Tamar, for she was a virgin, and it seemed impossible for him to do anything to her.
Now Amnon had a friend named Jonadab son of Shimeah,4 David's brother. Jonadab was a very shrewd man.
References for 2 Samuel 13:3
He 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."
"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.' "