Genesis 35:22-26

While Israel was living in that land, Reuben [his eldest son] went and lay with Bilhah his father’s concubine, and Israel heard about it. N ow Jacob had twelve sons— The sons of Leah: Reuben, Jacob’s firstborn, then Simeon, Levi, Judah, Issachar, and Zebulun; and the sons of Rachel: Joseph and Benjamin; and the sons of Bilhah, Rachel’s maid: Dan and Naphtali; and the sons of Zilpah, Leah’s maid: Gad and Asher. These are the sons of Jacob born to him in Paddan-aram.