וְאַתֶּ֧ם תִּהְיוּ־לִ֛י מַמְלֶ֥כֶת כֹּהֲנִ֖ים וְג֣וֹי קָד֑וֹשׁ אֵ֚לֶּה הַדְּבָרִ֔ים אֲשֶׁ֥ר תְּדַבֵּ֖ר אֶל־בְּנֵ֥י יִשְׂרָאֵֽל׃
Kalian akan menjadi bagi-Ku kerajaan imam dan bangsa yang kudus. Inilah perkataan yang harus kau sampaikan kepada bani Israel.”
Zera Kodesh
And you shall be a kingdom of priests - that you shall minister to Me, in that you shall crown Me upon you. And that is why the first letters of these words [spell], kingdom (malkhut). And that is the essence of the receiving of the Torah, that we accept His Kingship upon us, may His name be blessed. And with this, that we accepted it, we became a kingdom of priests. And that is the idea of the two crowns that we had when we said, "We will do and we will listen." For we had two ornaments when we accepted His Kingship, may His name be blessed. And that is why afterwards, it is stated (Exodus 33:6), "So the Children of Israel stripped themselves of their ornaments from Mount Sinai on." For they [no longer] had their two ornaments mentioned above. And that is why the essence of everything is the acceptance of His Kingship, may His name be blessed, with a full heart and soul.
Rashi
ואתם תהיו לי ממלכת כהנים AND YE SHALL BE UNTO ME A KINGDOM OF כהנים — i. e. princes, just as you say, (II Samuel 8:18) “And the sons of David were princes (כהנים)”, which cannot denote priests since his sons were of the tribe of Judah and not of Levi, the priestly tribe.
Chizkuni
ואתם תהיו לי ממלכת כהנים “You are to become for Me, a kingdom of priests.” All this is the result of My fondness for you and My authority to do so since I own the universe.