Commentaire sur La Genèse 49:8

יהודה אתה יודוך אחיך THOU JUDAH, THY BRETHREN SHALL PRAISE THEE — Because he rebuked the first three tribes in harsh terms Judah began to move away that he (Jacob) should not censure him for the incident with Tamar; Jacob therefore recalled him with words that would soothe him: Judah, you are not like these! — you your brethren may indeed praise (Genesis Rabbah 99:5).

יהודה אתה יודוך אחיך, anyone who interprets these words to mean that the brothers ought to praise Yehudah is grossly mistaken. The reason that Yaakov transfers the status of leader of the brothers, and, ultimately, hereditary royalty to Yehudah, was not his excellence as much as his older brothers’ unfitness. Yehudah’s elevation to this status would be initiated by his own brothers by their own volition, not through his father imposing him on the rest of the brothers. (compare the end of our verse “and the sons of your father will prostrate themselves before you.”) In Numbers 26,20 when Moses appoints Joshua as his successor, G’d suggests that he on his own account transfer his mantle of leadership to Joshua, [although G’d could have removed it from Moses and then Himself have bestowed it on Joshua. Ed.]

יהודה אתה, “you are the one who is fit to fill the position of royalty. The reason is that you are not stained with fatal flaws which would disqualify you from becoming king.