"Now the sons of Jacob were twelve in number. The sons of Leah: Reuben - Jacob's first born - Simeon, Levi, Judah, Issachar, and Zebulun. The sons of Rachel: Joseph and Benjamin. 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 who were born to him in Paddan-aram".
Bereshit, 35, 22-26
(JPS Tanakh)
