Genesis

²And Judah saw there a daughter of a certain Canaanite whose name was Shua; and he took her, and went in unto her. ³And she conceived, and bare a son; and he called his name Er. ⁴And she conceived again, and bare a son; and she called his name Onan. ⁵And she yet again bare a son, and called his name Shelah: and he was at Chezib, when she bare him. ⁶And Judah took a wife for Er his firstborn, and her name was Tamar. ⁷And Er, Judah's firstborn, was wicked in the sight of the LORD; and the LORD slew him. ⁸And Judah said unto Onan, Go in unto thy brother's wife, and perform the duty of an husband's brother unto her, and raise up seed to thy brother.