1)
What is "Kedoshchem"?
1.
Radak: I sanctify My name amidst you, like Koresh said "Kol Mamalachos ha'Aretz Nasan Li Hashem Mi Vachem mi'Kol Amo Yehi Elokav Imo v'Ya'al [li'Yrushalayim]" (Ezra 1:3).
2.
Malbim: I did so amidst the Kedushah of your deeds.
2)
Why does it say "Borei Yisrael"?
1.
Radak: This is like I explained "Bora'acha Yakov" (1; recognize that I created you, and the world).
3)
What is "Malkechem"?
1.
Radak: He is truly your king. He will not abandon you in the hands of the kings of the nations.
2.
Malbim: If you do not merit that I save you amidst Kedushah of your deeds, I will do so because I am Malkechem, like a king who redeems his servants even if they are not worthy.