Why does it say "Al Kol ha'Aretz" refer?
Malbim: Their purpose was not only for Ashur. Rather, no nation will subjugate Yisrael.
What is the significance of "ha'Yad ha'Netuyah"?
Radak: Once Hashem's hand was stretched over [Ashur] and struck it, all nations rebelled and feared Hashem. Anshei Kush and Egypt, who were in his camp (Ashur defeated them before coming to Yerushalayim) and saw Ashur's fall, they served Hashem and feared Him - "Yihyeh Mizbe'ach la'Shem b'Soch Eretz Egypt" (19:19).
To whom does "Kol ha'Goyim" refer?
Rashi: It is Ashur in its time, and Bavel in its time.
Radak: It says "Kol ha'Aretz" and "Kol ha'Goyim", for Melech Ashur conquered all lands, and his fear was on all nations.
Malbim: Any nation that will dare to subjugate Yisrael, also they will fall via Hashem, like Ashur did. If the counsel was only for Ashur, it would have sufficed for them to fall in their land via a natural cause.
