申命記 21:17

卻要認所惡之妻生的兒子為長子，將產業多加一分給他；因這兒子是他力量強壯的時候生的，長子的名分本當歸他。」

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.