This article is about David's daughter. You may be looking for Er's wife.
Tamar was daughter of David, the sister of Absalom. His half-brother Amnon was infatuated with her to the point where his friend Jonadab conceived a plot for him to be alone with her. Pretending to be sick, Amnon had his father the king summon Tamar to make cakes for him to eat out of her hand. She came and made the cakes, but Amnon wouldn't eat until everyone left. When it was just the two of them alone with each other, Amnon grabbed Tamar and forced her to lie with him. Tamar refused and tried to talk her way out of the situation, but Amnon wouldn't listen; he raped her and then forced her to leave, bolting the door shut behind her. Tearing her virginal tunic of many colors and casting dust upon her head, Tamar went to her brother Absalom weeping, who told her not to take the thing to heart because he is her brother. Tamar lived the rest of her life as a desolate woman in Absalom's house.