A kohen in the Hebrew Scriptures exists to do one thing: to mediate, to stand between, to bring near what cannot come near on its own. The priest is the one in the middle. That is the whole function of the office, from the sons of Aharon at the altar to the high priest who alone passed through the veil.

Which is exactly why the new covenant is so quietly explosive. Yirmeyahu, Jeremiah 31:34 promises that "they shall all know Me, from the least of them to the greatest," with no one left to teach his neighbor "Know YHWH." The defining content of the brit chadashah is unmediated access. A covenant whose whole substance is direct knowledge of the Father leaves the mediating office with nothing left to mediate. The instant the covenant is cut, the middle is empty.

This is the irony the cup exposes: the act that retired the mediator was rebuilt into a permanent office of mediation. The covenant that dissolved the need for a kohen standing between God and His people became the basis for a class of men whose work was to keep standing there. The cup does not found a priesthood. If anything, it dissolves the need for one.