Deuteronomy 21:15-17 In case a man should come to have two wives, the one loved and the other disliked, and they bear sons for him, the loved and the disliked, but the firstborn is the son of the disliked one,

CLV⁽ⁱ⁾ ¹⁵ In case a man should come to have two wives, the one loved and the other disliked, and they bear sons for him, the loved and the disliked, but the firstborn is the son of the disliked one, ¹⁶ then it will come to be in the day when he gives allotments to his sons of that which is his, that he should not be able to treat as firstborn the son of the loved in preference to the son of the disliked, who is the firstborn. ¹⁷ For he shall recognize the firstborn son of the disliked by giving to him a double share of all that is being found his; since he is the beginning of his virility, the customary right of the firstborn belongs to him.