Rashi

אראנו I SEE HIM — I see the preeminence of Jacob and his greatness, but it is not now (ולא עתה), but will be after some time.
דרך כוכב A STAR COMETH OUT [OF JACOB] — Understand this as the Targum does (“a king will arise from Jacob”). The word דרך has the same meaning as in (Lamentations 2:4): “He has bent (דרך lit., trodden) his bow; this expression is used because the star shoots across [the heavens] as an arrow does when the bow is trodden. In O. F. destent. It is as much as to say, “Prosperity (a good fortune) will rise”.
וקם שבט AND A שבט RISES [OUT OF ISRAEL] — a king, who chastises with the rod (שבט) and has sovereign power.
ומחץ פאתי מואב AND PIERCETH THE CORNERS OF MOAB — This is a reference to David of whom it is stated, (II Samuel 8:2) “[And he smote Moab] … making them to lie down on the ground and he measured two lines to put to death etc.”.
וקרקר AND UNDERMINETH — This is an expression denoting “digging”, as in (2 Kings 19:24): “I have dug (קרתי)”; (Isaiah 51:1): “The hole of the pit from which you were dug out (נקרתם); (Proverbs 30:17) “The ravens of the valley shall dig it out (יקרהו)". In O. F. forer.
כל בני שת ALL THE CHILDREN OF SETH — i.e., all nations, because all of them issued from Seth, the son of Adam, the first man (cf. Onkelos).