Genèse 49:8

Jehuda, thou didst make confession in the matter of Tamar: therefore shall thy brethren confess thee, and shall be called Jehudain from thy name. Thy hand shall avenge thee of thy adversaries, in throwing arrows upon them when they turn their backs before thee; and the sons of thy fathers shall come before thee with salutations.

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.]

יודוך, they will crown you. The word is abbreviated in its spelling, being the equivalent of יהודוך, (as in Psalms 45,18) Similar constructions [a letter being omitted, Ed.] are found in Kings II 6,27 where we have יושיעך instead of יהושיעך). The latter and proper spelling is found in Samuel I 17,47 i.e. יחושיע. At any rate, even though the word יודוך is derived from הוד as in הוד מלכות, “regal majesty,” the letter י is not an integral part of the word, but is added as part of the constructions known as חטופי פ'ה, the first root letter in roots commencing with the letter ה being shortened in sound. When we encounter to word הוציא, a transitive past construction derived from the root יצא, the first root letter of יצא has actually been omitted, the letterה in הוציא not being part of the root, but substituting for the letter י of the root. The same is true of the root ישב and the transitive construction of that verb as הושיב. We encounter the same phenomenon in Exodus 15,5 where the Torah wrote ירה בים. In our case the root of יודך is הרה. [The author quotes more examples of this kind, which I think we can skip. Ed.]

וישתחוו, in order to enthrone you.

בני אביך, Yaakov chose this formulation because having had four wives it was the simplest way. On the other hand, when Yitzchok (who had only one wife) blessed Yaakov, he spoke of בני אמך, “the sons of your mother” (27,29)

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.

יודוך אחיך, your brothers will accept you as king as they admit that you are fit to rule.

ידך בעורף אויביך, so that they will flee from you so that you do not destroy them. We find a similar construction in Exodus 23,27 ונתתי את כל אויביך אליך עורף, “I will make all your enemies turn their backs on you.”

וישתחוו לך בני אביך; you will rule over all your brothers (fellow tribes), but not over all the other nations,

יהודה אתה יודוך אחיך, they will elevate you to the position of royalty instead of Reuven, for the royalty, or potential for royalty of which I have deprived him your brothers will bestow upon you. We have proof of this happening from Samuel II 5,1 when David was crowned in Chevron by all the tribes of Israel. We are told in Bereshit Rabbah 99,8 that when Yehudah saw that Yaakov suddenly served up Reuven’s sin, as well as that of his brother Shimon and Levi, he became afraid that his own sin with Tamar would be the next one to be referred to by his father. He only calmed down when Yaakov began his remarks to Yehudah with the words “your brothers will elevate you to the position of royalty because you had the strength of character to publicly acknowledge and repent your having slept with your daughter-in-law Tamar.”

ידך בעורף אויביך, a reference to King David, who was victorious in all his wars against his enemies. We have a parallel verse said by David himself in Samuel II 22,41 ואויבי תחת לי עורף, “He made my enemies turn tail before me.”

ישתחוו לך בני אביך, when they will observe that you are successful, then they will prostrate themselves before you and declare that you are fit to be their king. When Yitzchok blessed Yaakov in Genesis 27,29 he referred to “the sons of your mother” prostrating themselves before him. Seeing that Yitzchok had only one wife this was quite normal. Seeing that Yaakov had four wives it would not have been good enough to refer to the sons of Yehudah’s mother, as that would have included only half the tribes. By phrasing the blessing as applicable to the “sons of your father,” Yaakov included all 12 tribes.

יהודה, אתה יודוך אחיך, “Yehudah your brothers will agree to your becoming king;” (your father’s sons will prostrate themselves before you [end of the sentence] (B’reshit Rabbah 99,8) We find this prediction having come true in the time of King David.. The numerical value of the letters in the word “Yehudah,” equals 30, corresponding to the 30 qualities required of a person who is fit to become Royalty. (Ethics of our fathers, 6,6) The thirty qualities (virtues, and privileges accorded) referred to have been enumerated in the Talmud tractate Sanhedrin, folio 18. An alternate interpretation of the words: יודוך אחיך: all the Israelites collectively, not only the members of his tribe will become known as יהודים, “Jews,” derived from his name Yehudah. (B’reshit Rabbah 98,6) Not only this, but the Messiah, the king of the Israelites after the final redemption will be descended from him.