Tamar was the widow of Judah's oldest son. According to custom, she was supposed to marry Judah's second son, Onan. If a child was born, that child would be considered the offspring of her first husband. But Onan did not carry out his duties according to the law, and because of this, he was struck dead by God.
Judah's third son, Shelah, was next in line to marry Tamar, but Judah withheld Shelah from the marriage, fearing that he too would die. Tamar then disguised herself as a harlot, and was hired by Judah - who did not reconize the harlot as his former daughter-in-law. Tamar demanded Judah's staff and seal as a pledge of payment for her services. When she became pregnant, Tamar brought forth Judah's staff and seal, proving Judah was the father. She bore twin sons, Perez and Zerah. Perez was an ancestor of Jesus. (Genesis 38:6-30).
Tamar, daughter-in-law of Judah, is mentioned seven times in six verses, in Genesis 38:6, 11, 13, 24; Ruth 4:12; 1 Chronicles 2:4; Matthew 1:3.
Tamar means "date palm."
There are two other women named Tamar in the Bible.
Next person in the Bible: Tamar, daughter of King David