Genesis 35:25

While Israel lived in that land, Reuben went and lay with Bilhah, his father’s concubine, and Israel heard of it.

Now the sons of Jacob were twelve.

The sons of Leah: Reuben (Jacob’s firstborn), Simeon, Levi, Judah, Issachar, and Zebulun.

The sons of Rachel: Joseph and Benjamin.

The sons of Zilpah (Leah’s servant): Gad and Asher. These are the sons of Jacob, who were born to him in Paddan Aram.

Jacob came to Isaac his father, to Mamre, to Kiriath Arba (which is Hebron), where Abraham and Isaac lived as foreigners.

The days of Isaac were one hundred eighty years.