Genesis 35:21-23 Young's Literal Translation (YLT)
21 And Israel journeyeth, and stretcheth out his tent beyond the tower of Edar;
22 and it cometh to pass in Israel's dwelling in that land, that Reuben goeth, and lieth with Bilhah his father's concubine; and Israel heareth.
23 And the sons of Jacob are twelve. Sons of Leah: Jacob's first-born Reuben, and Simeon, and Levi, and Judah, and Issachar, and Zebulun.