What does the verse say about crushing under His legs?
Rav Sadya Gaon: He did not want to crush us under His authority.
Rashi: Also this "was not mi'Libo" (33, from His desire; our sins caused everything).
Palgei Mayim: This is said in astonishment. Do you think that Nebuchadnetzar himself intended to crush the entire world under his legs?
Why does it say "Kol Asirei Aretz"?
Ibn Ezra: The verse depicts that Hashem is in Shamayim, and people are incarcerated on the land; the Ofan 1 locks them in.
Ri Kara #1: These are people afflicted with afflictions.
Ri Kara #2: They are humbled via exertion.
Palgei Mayim: It is as if the entire world was incarcerated under Nebuchadnetzar with their hands and feet. This is not natural!
Magihah (in Toras Chayim): I.e. the Galgal (sphere that moves Heavenly bodies).