“Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but, forasmuch as he defiled his father's bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright.”
Cross references: : Gen. 35:22 ; Gen. 49:4 Because they were made two tribes, they had a double portion.