TSK · Numbers 26:5

While Israel was living in that land, Reuben went to bed with Bilhah, his father’s concubine, and Israel heard about it.Jacob had twelve sons:

These are the names of the sons of Israel who went to Egypt– Jacob and his sons: Reuben, the firstborn of Jacob.

The Ancestry of the Deliverer 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.

Reuben’s Descendants 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.