Now David’s son Absalom had a beautiful sister named Tamar. In the course of time David’s son Amnon fell madly in love with her. ¹ 

He asked Amnon, ¹  “Why are you, the king’s son, ²  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.”

Absalom had made Amasa general in command of the army in place of Joab. (Now Amasa was the son of an Israelite man named Jether, who had married ¹  Abigail the daughter of Nahash and sister of Zeruiah, Joab’s mother.)