But Jacob said, “Swear an oath to me now.” ¹  So Esau ²  swore an oath to him and sold his birthright ³  to Jacob.

The sons of Reuben, Israel’s firstborn – (Now he was the firstborn, but when he defiled his father’s bed, ¹  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. ²