2 Samuel 13:22
And Absalom spake unto his brother Amnon neither good nor bad: for Absalom hated Amnon, because he had forced his sister Tamar. And Absalom spake unto his brother Amnon neither good nor bad: for Absalom hated Amnon, because he had forced his sister Tamar.
Absalom hated his brother Amnon because Amnon had forced Tamar, who was Absalom's sister. He spoke to Amnon neither good nor bad, keeping his vengeful purpose hidden for two years before acting. At the end of that time he avenged the violation of Tamar by having Amnon put to death, slaying him for the great crime.
That hatred and revenge were bitter fruit of David's own wrongdoing, with David's sons repeating sins he himself had committed. Amnon's crime and Absalom's revenge kept David's sin continually before his mind. In them he was made to feel the full weight of the injustice he had done to Uriah and Bath-sheba.