This is a very sad story. Absalom's half-brother, Amnon raped the beautiful Tamar, Absalom's sister. 2 Samuel 13:14-22 (NIV), “he (Amnon) was stronger than she, he raped her. Then Amnon hated her with intense hatred. In fact, he hated her more than he had loved her. Amnon said to her, 'Get up and get out!’ Tamar put ashes on her head and tore the ornate robe she was wearing. She put her hands on her head and went away, weeping aloud as she went.
“Her brother Absalom said to her, 'Has that Amnon, your brother, been with you? Be quiet for now, my sister; he is your brother. Don’t take this thing to heart.’ And Tamar lived in her brother Absalom’s house, a desolate woman.
“When King David heard all this, he was furious.
“And Absalom never said a word to Amnon, either good or bad; he hated Amnon because he had disgraced his sister Tamar.”
When King David heard about this tragedy, he should have sought justice for Tamar. There were judges in Israel who had the legal responsibility to pass judgment. But the scriptures only record that David was furious. Absalom was so enraged that he hated Amnon. However, neither David nor Absalom obeyed God's ordinances. Leviticus 18:11, 29 (NLT), “Do not have sexual relations with your stepsister, the daughter of any of your father’s wives, for she is your sister…‘Whoever commits any of these detestable sins will be cut off from the community of Israel." Amnon should have been tried and exiled from Israel.
Over a period of two years, Absalom's hatred for Amnon grew. He plotted revenge, and finally did have his men murder Amnon. But God is the ultimate judge; no man may take the Law into his own hands. Deuteronomy 32:35 (NASB) states, "‘Vengeance is Mine, and retribution." Thus, Absalom had the spirit of rebellion against God.
His rebellion was further manifested when he acted like a judge. 2 Samuel 15:2-6(NLT), "He got up early every morning and went out to the gate of the city. When people brought a case to the king for judgment…Absalom would say, “You’ve really got a strong case here! It’s too bad the king doesn’t have anyone to hear it. I wish I were the judge….and I would give them justice!”…Absalom did this with everyone who came to the king for judgment, and so he stole the hearts of all the people of Israel."
Again, Absalom rebelled against God's anointed, King David, and tried to take the kingdom for himself. It is true that David should have turned Amnon over to Israel's judges, but that did not justify Absalom's treasonous behavior. His behaviors were worthy of judgment and death. 1 Samuel 15:23 (NLT), "Rebellion is as sinful as witchcraft, and stubbornness as bad as worshiping idols."