While Israel was living in that land, Reuben had sexual relations with Bilhah, his father’s concubine, and Israel heard about it. Jacob had twelve sons:
The sons of Judah: Er, Onan, and Shelah. These three were born to him by Bathshua, a Canaanite woman. Er, Judah’s firstborn, displeased the Lord, so the Lord killed him.