Genesis 38:6-16

And Judah took a wife for Er his firstborn, whose name was Tamar. And Er, Judah's firstborn, was wicked in the sight of the LORD; and the LORD slew him. And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother. And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest that he should give seed to his brother. And the thing which he did displeased the LORD: wherefore he slew him also. Then said Judah to Tamar his daughter in law, Remain a widow at thy father's house, till Shelah my son be grown: for he said, Lest peradventure he die also, as his brethren did. And Tamar went and dwelt in her father's house. And in process of time the daughter of Shuah Judah's wife died; and Judah was comforted, and went up unto his sheepshearers to Timnath, he and his friend Hirah the Adullamite. And it was told Tamar, saying, Behold thy father in law goeth up to Timnath to shear his sheep. And she put her widow's garments off from her, and covered her with a vail, and wrapped herself, and sat in an open place, which is by the way to Timnath; for she saw that Shelah was grown, and she was not given unto him to wife. When Judah saw her, he thought her to be an harlot; because she had covered her face. And he turned unto her by the way, and said, Go to, I pray thee, let me come in unto thee; (for he knew not that she was his daughter in law.) And she said, What wilt thou give me, that thou mayest come in unto me?