Why does it say "Nisgav Hashem"?
Radak: In this salvation He is elevated. Nations will elevate him for this miracle, and admit that He dwells above, and He can lower the high and raise the lowly. He lowered Machaneh Ashur, which came against Yerushalayim with open strength. He elevated residents of Tziyon, who were lowly, and filled Tziyon with Mishpat and Tzedakah.
Why does it say that Hashem is "Shochen Marom"?
Rashi: He showed His Gevurah, that He is elevated above all. His hand is on top.
Malbim: This is how He is Nisgav (elevated).
Why does it say "Malei Tziyon"?
Radak: From that day and onwards they will do Mishpat Tzedakah in Tziyon. Targum Yonasan is like this.
Malbim: Hashem filled Tziyon with matters greater than the spoils that they lost - Tzedek and Mishpat. Via this, they returned to Hashem and began to do Mishpat and Tzedakah, which is more coveted than anything.
