Genesis 49:3

Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power:

Reuben, thou art my first-born. In polygamous families there are sometimes several first-borns; and Jacob, had he been at liberty to follow his own predilections, would doubtless have assigned the honour as well as the rights of primogeniture to Joseph, the first-born of his beloved Rachel. [But bªkowr (H1060), when used in regard to human offspring, denotes the oldest son on the father's side, and accordingly it frequently occurs in parallelism with "the beginning of strength" (cf. Deuteronomy 21:15; Deuteronomy 21:17; Psalms 78:51; Psalms 105:36). Hence, the Septuagint renders it in the passage before us as: archee teknoon mou.] Since the first begotten, then, in Jacob's family, Reuben would "excel in dignity and in power" all his brothers. But in consequence of his atrocious crime (see the note at Genesis 35:22) he was deprived of this preeminence, belonging to the birthright, which included, according to Jewish writers, a double portion of the inheritance, the priesthood, and the kingdom, and which were distributed among his brothers-the first being conferred on Joseph, the second on Levi, and the third on Judah.