Commentary for Numbers 24:19

וירד מיעקב AND OUT OF JACOB ONE SHALL RULE — and there will be yet another ruler from Jacob,

And the meaning of the verse, and he shall destroy the remnant from ‘the’ city,²⁵⁵Verse 19. is “from ‘every’ city,” for there will not be left a remnant of any city in the world [i.e. of those belonging to the Roman Empire, here referred to by the names Edom and Seir]. Thus at first [in Verse 17] Balaam said that [the Messiah] will break down all the sons of Seth, and now he is saying that he will not leave any remnant or survivor [of them]. Thus was completed Balaam’s counsel to Balak.

וירד מיעקב, "and someone from Jacob will exercise dominion, etc." According to Rabbi Abraham ibn Ezra Bileam referred to Yoav, David's commander-in-chief. Rashi understands the verse as a reference to King Messiah. I believe that Rashi is correct. If Ibn Ezra had been correct this verse should have preceded the verse predicting the downfall of Edom, as the wars under the leadership of David and Yoav against Moav certainly preceded the downfall of Edom. Edom's downfall is always equated with ushering in the age of the Messiah. Rashi's explanation means that although Bileam had already described the defeat of all the descendants of Sheth, i.e. of all mankind, he wants to tell us that Bileam here gives notice that there will be numerous survivors of the war against Edom and the descendants of Sheth. However, none of these survivors will ever again establish an independent state as previously but they will be ruled over by Jacob.