John Wesley on Genesis 49:3

Reuben thou art my first - born - Jacob here puts upon him the ornaments of the birth - right, that he and all his brethren might see what he had forfeited and in that might see the evil of his sin. As the first - born he was his father's joy, being the beginning of his strength. To him belonged the excellency of dignity above his brethren, and some power over them.