Aharon haKohen and kedushas Am Yisrael

R’ Tzadok haKohen, Yisrael Kedoshim 7b:

“V’heyisem li kedoshim [ki kadosh ani] – mah ani kadosh, af atem…” (Toras Kohanim) obligates one to strive to achieve the greatest heights of kedusha, kedusha comparable to G-d’s kedusha, as much as human effort allows. Through these efforts G-d will [in turn] from above [reciprocate] with kedusha, separating [the nation] from all tumah and evil so they holds no power or sway, and no nation or people will be able to rule over [the Jewish people]… The dominion of other nations is caused by an erosion of the recognition of that singular sense of kedusha. Therefore, when Aharon died and the Ananei haKavod vanished the King of Arad attacked and took captives, because Aharon was the kodesh kodashim, embodying the greatest revalation of kedusha possible in olam hazeh.