Reuben thou art my firstborn, the beginning of the strength of my generation, and the chief event of my thoughts To thee belonged the birthright, and the high priesthood, and the kingdom: but because thou hast sinned, my son, the birthright is given to Joseph, and the, kingdom to Jehuda, and the priesthood to Levi.
Why Reuben Lost the Birthright, Priesthood, and Crown
Targum Pseudo-Jonathan on Genesis 49:3