And when he was living in that region, Reuben went out, and he slept with Bilhah the concubine of his father, which was not such a small matter as to be hidden from him. Now the sons of Jacob were twelve.
Also, there were the sons of Reuben, the firstborn of Israel. For indeed, he was his firstborn, but when he had violated the bed of his father, his right as firstborn was given to the sons of Joseph, the son of Israel, and he was not reputed as firstborn.
Of Ruben, the firstborn of Israel, by their generations and families and houses, and the names of each head, of all who were of the male sex, from twenty years and above, capable of going to war,
Instead, he shall acknowledge the son of the hated wife as the firstborn, and he shall give to him a double portion of all that he has. For he is the first among his children, and the rights of the firstborn are owed to him.