Sforno on Genesis 49:10/ספורנו על בראשית מ״ט:י׳

1לא 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.

2ומחוקק 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.

3עד 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,

4ולו 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.