2 Samuel 13:20-22

So her brother Absalom said to her, “Has your brother Amnon been with you? But now keep silent, my sister; he is your brother; do not take this matter to heart.” So Tamar remained secluded in her brother Absalom’s house. Now when King David heard about all these things, he was very angry [but failed to take any action]. But Absalom did not speak to Amnon either good or bad; for Absalom hated Amnon because he had violated his sister Tamar.