16 then it hath been, in the day of his causing his sons to inherit that which he hath, he is not able to declare first-born the son of the loved one, in the face of the son of the hated one -- the first-born.
16
when he wills his property to his sons, he must not give the rights of the firstborn to the son of the wife he loves in preference to his actual firstborn, the son of the wife he does not love.
Young's Literal Translation is in the public domain.