So Leah became pregnant and gave birth to a son. She named him Reuben, for she said, “The Lord has looked with pity on my oppressed condition. Surely my husband will love me now.”
While Israel was living in that land, Reuben had sexual relations with Bilhah, his father’s concubine, and Israel heard about it. Jacob had twelve sons:
The sons of Reuben, Israel’s firstborn – (Now he was the firstborn, but when he defiled his father’s bed, his rights as firstborn were given to the sons of Joseph, Israel’s son. So Reuben is not listed as firstborn in the genealogical records.
These are the heads of their fathers’ households: The sons of Reuben, the firstborn son of Israel, were Hanoch and Pallu, Hezron and Carmi. These were the clans of Reuben.
And they were as follows: The descendants of Reuben, the firstborn son of Israel: According to the records of their clans and families, all the males twenty years old or older who could serve in the army were listed by name individually.