Per Exodus 29:6 the High Priest is to wear a crown, while the king is to write himself a copy of the Torah. Leaders must hold themselves to higher standards. They must guard their ears, actions, and every step (v20).
The roles of priest and king somewhat overlap and this foreshadows the Melchizedek nature of Messiah's priesthood. The High priest is man elevated toward God. Messiah is God brought down to man. Like Messiah #yeshua, the Lamb slain from the foundation of the world, the Aaronic priesthood is forever, according to Exodus. It cannot be revoked so long as heaven and earth remain or else God lied to Aaron and Pinchas. Who is God that he should lie?
Unlike Yeshua, however, the Aaronic priesthood is permanently tied to Zion. Yeshua is a priest of a higher order and serves in a higher temple.