What is the meaning of "Hen Gur Yagur Efes me'Osi"?
Rashi: He will fear evil decrees, the one whom I am not with, i.e. Sa'ir.
Radak citing Targum Yonasan: This is gathering, like "Yaguru Alai Azim" (Tehilim 59:4). The simple meaning is, nations will gather against you "Efes me'Osi" - not via My command. Other times I commanded, e.g. Sancheriv and Nebuchadnetzar. These, Gog and Magog, will gather against you on their own. Even though it says "v'Ha'alisicha mi'Yarkesei Tzafon v'Havi'osicha Al Harei Yisrael", "Ya'alu Devarim Al Levavecha" (Yechezkel 39:2, 38:10), - Hashem put in their hearts to come for Yisrael's benefit, and not to harm Yisrael. He will take Yisrael's vengeance from them, and from other Nochrim who harmed Yisrael. This will be in Eretz Yisrael, for the honor of His name and of Yisrael and their benefit, i.e. the spoils.
Malbim: Will someone make war, and it is not from Me, that I did not send him?!
Why does it say "Mi Gar Itach Alayich Yipol"?
Rashi citing Yevamos 24b: We do not accept converts in the era of Mashi'ach [and we did not accept in the days of David and Shlomo]. Only one who dwells with us (converts) in our poverty, will be Nofel (receive a portion) with us in the world to come. This is like "Al Pnei Chol Echav Nafal" (Bereishis 25:18).
Rashi #1: One who gathers against you for war. Radak - he will fall - "Al Harei Yisrael Tipol" (Yechezkel 39:4).
Rashi #2: One who is Misgareh (confronts) you.
Malbim: Since without Me, "Nig'al Magen Giborim" (Shmuel I, 21:1; shields are not oiled for war), who will fight you to kill you, and who will fall upon you to plunder your money?! These correspond to "[Rachaki] mi'Mechitah" and "Rachaki me'Oshek" (14), respectively.
