Encyclopedie , Jewish Encyclopedia, TAMAR (2), Isidore Singer Jacob Zallel Lauterbach, TAMAR;
2.—Biblical Data: Sister of Absalom, and the victim of the passion of her half-brother Amnon. At the suggestion of Jonadab, his confidant, Amnon feigned illness, and Tamar was sent by the king to his apartment to prepare food for him. Amnon took advantage of this opportunity to dishonor her forcibly, after which he drove her away. Weeping and lamenting, she went to her brother Absalom, in whose house she remained. Absalom avenged his sister two years later by killing Amnon (II Sam. xiii.).
—In Rabbinical Literature:
Tamar was the natural daughter of David by a captive whom he married after she had abjured her Gentile religion, and who became the mother of Absalom. Because of her illegitimacy it would have been lawful for her to marry Amnon, the son of David, and she therefore besought him (II Sam. xiii. 13) not to dishonor her, but to ask the king to bestow her on him as his wife, a request which would surely have been granted (Sanh. 21a).