Matthew Poole and continuators on Genesis 49:3

3 Reuben thou art my first-born, my might, and the beginning of my strength , the excellency of dignity, and the excellency of power .

The first instance or evidence of my might or strength, or of that masculine vigour, whereby God enabled me to beget a Child. Compare Deut. 21. 17. Psal. 105. 36. Or the first of my Children, which are the strength, the stays and supports, of a Father and of his Family, thence called his Arrows, as Psal. 12[illegible: 1+ letters]. 4. and by other authors, the pillars of the house.

As firstborn thou hadst the right of precedency before all thy brethren in point of dignity and power or priviledge, the double portion, the Priesthood, the Dominion over thy brethren were thine.