What does "Mamleches Kohanim" mean?
Rashi: It means a kingdom of princes. 1
Ramban: A kingdom of people who serve Me. 2
Seforno and Targum Onkelos: A kingdom of Kohanim - to teach all the nations to call in the Name of Hashem and to worship Him. 3
Targum Yonasan: It means a nation of kings, who are crowned with the crown of Torah and of Kohanim 4 who serve Hashem.
Meaning that every Jew will be a prince.
As if to say that Yisrael is to the nations of the world what Kohanim are to Yisraelim.
As the Pasuk indicates in Yeshayah (61:6) and (2:3 - "For Torah will go out from Tziyon"] Seforno).
Indicating that the crown of Torah incorporates the crown of kingship and the crown of Kehunah (Na'ar Yonasan citing Rabeinu Bachye).
What is meant by "Goy Kadosh"?