Hebrews 7:11-17

Now if perfection was through the Levitical priesthood (for on the basis of it the people received the Law), what further need was there for another priest to arise according to the order of Melchizedek, and not be designated according to the order of Aaron? For when the priesthood is changed, of necessity there takes place a change of law also. For the one concerning whom these things are spoken belongs to another tribe, from which no one has officiated at the altar. For it is evident that our Lord was descended from Judah, a tribe with reference to which Moses spoke nothing concerning priests. And this is clearer still, if another priest arises according to the likeness of Melchizedek, who has become such not on the basis of a law of physical requirement, but according to the power of an indestructible life. For it is attested of Him, “YOU ARE A PRIEST FOREVER ACCORDING TO THE ORDER OF MELCHIZEDEK.”