Genèse 49:10

Kings shall not cease, nor rulers, from the house of Jehuda, nor sapherim teaching the law from his seed, till the time that the King the Meshiha, shall come, the youngest of his sons; and on account of him shall the peoples flow together.

THE SCEPTRE SHALL NOT DEPART FROM JUDAH. Its purport is not that the sceptre of royalty shall never depart from Judah, for it is written, The Eternal will bring thee, and thy king whom thou shalt set over thee, unto a nation that thou hast not known, thou nor thy fathers, with the result that the people and their king will be in exile, devoid of royalty and nobility, and for a long time there has not been a king in Israel! The prophet Jacob did not assure Israel that they would not enter captivity under any circumstances because Judah would rule over them. Instead, the purport of the verse before us is that the sceptre shall not depart from Judah to any of his brothers, for the king of Israel, who will rule over them, will be from the tribe of Judah, and none of his brothers will rule over him. The same meaning applies to the expression, there shall not depart a lawgiver from between his feet, which means that every lawgiver in Israel who carries the king’s signet shall be from Judah. It is he who will rule and command in all Israel, and he will have the seal of royalty until the coming of his son, who [will have] the obedience of all people, to do with all as he pleases, this being a reference to the Messiah. “The sceptre” is thus an allusion to David, who was the first king to have the sceptre of royalty, and “Shiloh”, “until Shiloh come, and his be the obedience of peoples.” is his son, who will have the obedience of the peoples.
Rabbi Abraham ibn Ezra’s assertion that “Shiloh” is a reference to David is impossible for Judah never possessed a royal sceptre prior to David. And even though the tribe of Judah was honored and marched first in the desert, the word sheivet (sceptre) applies only to a king or prince, as it is written: A sceptre (‘sheivet’) of equity is the sceptre of thy kingdom; the sceptre of the rulers; a sceptre to rule.
Now this verse before us alludes to the fact that Jacob made the tribe of Judah king over his brothers and bequeathed to Judah sovereignty over Israel. This is what David said: And the Eternal, the G-d of Israel, chose me out of all the house of my father to be king over Israel forever; for He has chosen Judah to be prince, and in the house of Judah, the house of my father, and among the sons of my father He took pleasure in me to make me king over all Israel.
Jacob said, It shall not depart, in order to allude to the fact that another tribe will rule …

לא יסור שבט מיהודה, the position of royalty which all his 12 brothers bestowed on him, i.e. that they all prostrate themselves before him, will not be removed from him until Shiloh. Yehudah, i.e. King Rechavam of Yehudah son of Solomon who wanted to confirm his ascendancy to the throne in Shilo, which is very close to Shechem. (Kings I 12) [In the event, his stupidity in listening to inexperienced irresponsible counselors lost him most of his kingdom so that he ruled only over Yehudah and Binyamin. Ed.]

לא יסור שבט מיהודה, once he will have attained the formal position of king, as hinted at by the wordsוכלביא מי יקימנו in the previous verse, the scepter symbolising his rule will not move to any other tribal leader, unlike that of King Sha-ul, who, although crowned with G’d’s approval, was deprived of founding a dynasty by G’d Who had rejected him on account of his disobedience (a promise by the prophet Nathan to David who had also sinned, compare Samuel II 7,15). When the kingdom of Yehudah headed by a monarch of Davidic origin did collapse and was destroyed by the Babylonians, this did not contradict what Yaakov had predicted here that the scepter would not pass to others from the tribe of Yehudah. Yaakov spoke only about a period during which the state and the kingdom would continue to exist, prophesying that as long as that condition existed the rule would not be transferred to anyone belonging to another tribe. He had not addressed the possibility of Jewish statehood being lost altogether.

ומחוקק מבין רגליו, that his descendants would sit on the throne as judges, and that other members of his tribe would be among those who would be scribes for the judges as was the custom.

עד כי יבא שילה, the word שילה is a composite of the root שול meaning שולים, boundaries, margins. The other part of the word is based on the root שלה, the root of the word שלום. Shalom, commonly understood as “peace,” means “the end of the road,” after whatever wrangling in order to achieve an objective has been successfully concluded. Yaakov is saying that until the advent of שילה, i.e. the second part of that word, Yehudah’s pre-eminence will be marginal, narrowly bounded. Once the Messiah will arrive, however,

ולו יקהת עמים, nations will subordinate themselves to him displaying their weakness. The meaning of the word קהה as weakness is supported by Kohelet 10,10 אם קהה הברזל, “if the axe is blunt, etc.” A blunt blade is a weak blade. The survivors of the wars preceding the arrival of the Messiah will have been weakened sufficiently, heeding the instructions of the Messiah as predicted by Bileam in Numbers 24,17.

לא יסור שבט מיהודה, the ruler is called שבט because he exercises authority over the people and disciplines them if they disobey. He uses his power like a father uses his rod on a disobedient son. In fact, the rod or scepter, or its equivalent, are carried by people in authority in order to remind those who are subservient to them as a symbol of their power to exact punishment. We find such a שבט called שרביט הזהב, “the golden scepter,” and whether the king extended it or failed to extend it to a supplicant determined if he would be executed. (Esther 5,2) The expression also occurs in the sense we have mentioned in Isaiah 14,5 and in Psalms 45,7.

ומחוקק מבין רגליו, a reference to the sons of Yehudah, i.e. that his appointment as forecast by Yaakov will be hereditary, just as the priesthood is transferred from father to son. (if the son is worthy and the people do not object) The expression מבין רגליו is analogous to the afterbirth, which exits from between the mother’s legs (Deuteronomy 28,57) The reason why the king is referred to as מחוקק, is because he has the authority to legislate laws, חוקים. Yaakov said that this authority of an informal nature would not depart from Yehudah until he would have someone from his tribe who wields formal authority, i.e. is elected king, a reference to David.

שילה; a reference to David’s son, seeing that the meaning of the word is derived from Deuteronomy 28,57 ובשליתה, i.e. “and against her afterbirth, etc.” Onkelos understands the word as referring to the Messiah. He bases himself on the variant spelling here still having the same meaning as שלו, “his.” This is also the way Bereshit Rabbah 99,8 understands the word שילה in our verse. Yaakov would be saying that Yehudah’s preeminence would not be short-lived, but would continue until the coming of the Messiah, the one to whom royalty would belong permanently. The whole blessing to Yehudah could then be compared to a father saying to his son: “accept this token in the meantime until I can give you the real thing!”

ולו יקהת עמים. The word יקהת is a noun meaning “obedience,” as it is also in Proverbs 30,17 ותבוז לקהת אם, “and disdains to relate with obedience to his mother.” Yaakov predicts that all the nations will show obedience to the king stemming from Yehudah. This prophecy began to be fulfilled in the days of King David, and in an even greater measure during the reign of his son Solomon.

לא יסור שבט מיהודה, according to a Midrash this line is to be understood as in Jeremiah 2,21: “it will not blossom;” the word appears in this sense there סורי הגפן נכריה, “the vine blossomed into an alien vine.” In other words: Yaakov cautions that the rod of Yehudah as a ruler will not blossom forth

עד כי יבא שילה, “not until the Tabernacle in Shiloh will be ruined. The word יבא in this line does not mean “he will come,” but is an expression denoting ruin, just as in Isaiah 60,20: לא יבא עוד שמשך, “your sun will never set again;” An alternate interpretation of this verse: instead of referring to Yehudah’s ascent to the throne being still a long way off, Yaakov promises that once on the throne of the Kingdom of Yehudah, the rod symbolising the power of the holder of it will not be usurped per by another tribe, as it had been done after Saul’s dynasty collapsed until the coming of the Messiah, symbolised by the word שילה, in other words, not ever. G–d confirmed Yaakov’s promise to David in Samuel II 7,16: through the prophet Natan. A third possible interpretation of our verse; David will not lose the throne of all of Israel until after the fateful assembly in Sh’chem,- very close to Shiloh- when ten tribes crowned Jerobam as their king, and Rechavam, Solomon’s son retained the loyalty only of his own tribe and that of the tribe of Binyamin. Still another interpretation of our verse: in spite of many revolutions, exiles etc. that will occur after the first King from the tribe of Yehudah, David will ascend the throne, when the Messiah will arrive who will be from the tribe of Yehudah, and he will rule without anyone disputing his right to do so. (Attributed to Rav Rachmiel? Yitzchok)