Why is He called "Hashem Elokim Tzevakos"?
Radak: He is the Master of legions above and below, and everything is in His ability. He will destroy their land.
What is the meaning of "ha'Noge'a ba'Aretz va'Tamog"?
Rashi citing Targum Yonasan: He reprimands the land, and it trembles. Tamog is an expression of motion. I.e. this decree came from Me.
Radak: This is like it says above "Sirgaz ha'Aretz" (8:8), i.e. an earthquake. Water will be there; refer to 8:8:4:2. Va'Tamog is the land dissolving, like "bi'Rvivim Temogegenah" (Tehilim 65:11).
Malbim: Above, it says "ha'Al Zos Lo Sirgaz ha'Aretz" (8:8). This hints to the rebellion among them. The words imply that the land was agitated by itself. Here it explains that it was from Hashem. The verse depicts the rebellion as agitation of the land, and depicts the enemy sweeping the nation to Galus as the river rising to cover the land. This was not chance, rather, via Hashem. He touched the land and made the rebellion, like I explained "I saw Hashem standing by the Mizbe'ach" (refer to 9:1:1:4). He also caused the river to rise, and enemies covered the land.
Why does it say "v'Avlu Kol Yoshevei Vah"?
Radak: All its residents will be destroyed. Above (8:8) it says "v'Aval Kol Yoshev Bah" (singular), for the Klal. Here it is plural, for the individuals.
Here it says "v'Alsah cha'Y'or Kulah." Above, it says "v'Alsah cha'Or Kulah" (8:8)!
Radak: Above, the Yud is omitted. (The meaning is the same.)
