Why does it say "Hashem b'Tziyon Gadol"?
Radak: Then He will be great in Tziyon; He will aggrandize Himself over the Goyim when He does Mishpat to Resha'im.
Radak citing Shocher Tov: When He returns His Shechinah to Tziyon, He will be Gadol.
Malbim: The verses discuss three stages 1 . (a) When "Hashem b'Tziyon Gadol", "v'Ram Hu Al Kol ha'Umim." "Gadol" is unlike "Ram". Gadol spreads from above to below, like a pillar on the ground and its head is in Shamayim. Everyone attains from it according to his height. A midget holds the bottom of the pillar, and a giant holds the middle. When Hashem is in Tziyon, everyone attains from Him according to his perfection, be it little or much. He is found with every Yisrael, also the smallest. Also refer to 99:2:2:1.
What do we learn from "v'Ram Hu Al Kol ha'Umim"?
Malbim: Something Ram, e.g. a star in Shamayim, no person can attain it. So is Hashem to the Nochrim; they say that one cannot attain Him, and He does not supervise at all the lower world. This is when He hands them over to conduct of the Ma'arachah, and does not show them His Hashgachah.
