What do we learn from "Nichbados Medubar Bach"?
Rashi: [Hashem] said honorable things about you (Yerushalayim) - you are "Ir ha'Elokim."
Radak #1: Esteemed Midos are said about those who dwell in you (Yerushalayim).
Radak #2: Esteemed attributes are said about you (Yerushalayim). You are better than other lands in many ways. Civilization is divided into seven parts. Yerushalayim is in the middle - "Yoshevei Al Tabor ha'Aretz" (Yechezkel 38:12). Therefore its air is a better mix than all other airs for health and Chachmah - "Yefe Nof Mesos Kol ha'Aretz" (above, 48:3). Its air makes people wise (Bava Basra 158b).
Radak (7, from Shocher Tov): In the Beis ha'Mikdash, they 1 said Hashem's name like it is written, "Leyir'ah Es Hashem ha'Nichbad veha'Nora" (Devarim 6:24). It is said like it is written only in Ir ha'Elokim.
Malbim: Whenever Dibur is followed by Beis 2 , it is for detriment. Nations thought that Hashem's love of Sha'arei Tziyon shows the detriment of Yisrael (He does not love them - refer to 87:2:1:1). Such detriment is a great honor - it admits that you are Ir ha'Elokim, in which Hashem chose to dwell Keva (permanently), and amidst this He chose to dwell Keva amidst Yisrael!
Only the Kohen Gadol says it like it is written! (PF)
I.e. Bo, Bah, Bam, Banu, or a word starting with the prefix Beis. Radak (Yechezkel 33:30) agrees to this Klal, but says that here, "Nichbados" overrides this. (There are other exceptions, e.g. "Peh El Peh Adaber Bo" (Bamidbar 12:8), "v'Dibarta Bam" (Devarim 6:7)! - PF)
Why is it called "Ir ha'Elokim"?
Radak: Elokim chose to make His honor dwell there.
Malbim: Hashem chose to dwell there Keva (permanently).