2 Samuel 13:2

13:2 But Amnon became frustrated because he was so lovesick over his sister Tamar. For she was a virgin, and to Amnon it seemed out of the question to do anything to her.

2 Samuel 13:4

13:4 He 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.”