Where should they gather?
Radak: They should come close to Me.
Malbim: [First,] those of each country should gather.
What is the meaning of "Hisnageshu"?
Rashi: It is an expression of Hagashah (bringing close). The Nun is secondary, like Hisnagfu (Yirmeyah 13:16).
Malbim: Take counsel to investigate the Emes.
Who are "Pelitei ha'Goyim"?
Rashi: They are those who remained from the sword of Nebuchadnetzar.
Radak: They are the lowest of the Goyim, i.e. idolaters. It cannot be that there are not Chachamim among the Goyim who know that idolatry is folly. [Even] if [the lowest] are the majority, they are called Pelitei, i.e. the lowest. The same applies to "Pelitei Efrayim" (Shoftim 12:4).
Malbim: They are the remnant of the Nochri idolaters that will remain in the end of days.
The ones who carried their idol - what did they not know?
Rashi: They did not understand knowledge.
Radak: It what way is it god? [Even though] "he carries it and prays to it, [really] it is a god that does not save"!
Malbim: To whom they serve, and why. This is the contrary of the Torah that Hashem put in front of Yisrael - He informed them the reasons for the Mitzvos - "Lo Amarti l'Zera Yakov Tohu Vakshuni" (19).
What is the significance of praying to a god that does not save?
Malbim: Even their intent that the idol will direct their Tefilah to stars and bring down an influence, they will see that it does not help.