Why does it mention Tziyon and Yerushalayim?
Rashi: The remnant [from Tziyon] will settle in Tziyon, and the remnant from all places will dwell in Yerushalayim.
Radak #1: It is the head of Malchus Yisrael.
Radak #2: The war of Gog and Magog will be there.
Malbim: "Nish'ar" is left over with intent; Nosar is without intent. In Tziyon were the honored of Yisrael - the princes and Chachamim that the enemy intentionally left over (Daniel Perek 1). The remnant in Yerushalayim survived without the enemy's intent.
What is the meaning of "Kadosh Ye'amer Lo"?
Rashi: All will be Tzadikim. Radak - Kadosh will be said about each one, for he will be Kadosh.
What do we learn from "Kol ha'Kasuv la'Chayim bi'Yrushalayim"?
Rashi based on Targum Yonasan: Everyone written for life in the world to come will see [the consolation of Yerushalayim 1 ].
Radak: It will be decreed that he live, based on his straightness and good deeds. This is like "Mecheni Na mi'Sifrecha Asher Kasavta" (Shemos 32:32; people are written for life).
Malbim: Surely, also some Resha'im will survive 2 . Therefore, the verse teaches that only the survivors written for life are called Kadosh, but not those written "la'Charafos l'Dir'on Olam" (Daniel 12:2).
Ritva (Ta'anis 30b): There will be Techiyas ha'Mesim when the [third] Beis ha'Mikdash is built, for those who died in Galus and looked forward to salvation - "Ashrei ha'Mechakeh" (Daniel 12:12).
Above (1:28), Malbim said that "Ozevei Hashem" will cease from the world!
