申命记 21:17

却要认所恶之妻生的儿子为长子，将产业多加一分给他；因这儿子是他力量强壮的时候生的，长子的名分本当归他。」

But he shall acknowledge the son of the hated for the firstborn, by giving him a double portion of all that he hath: for he is the beginning of his strength; the right of the firstborn is his.