Genesis 35:22-24 New International Version - UK (NIVUK)
22 While Israel was living in that region, Reuben went in and slept with his father’s concubine Bilhah, and Israel heard of it.
Jacob had twelve sons:
23 The sons of Leah:
Reuben the firstborn of Jacob,
Simeon, Levi, Judah, Issachar and Zebulun.
24 The sons of Rachel:
Joseph and Benjamin.