Hebrews 7:10-14

for he was still in the loins of his forefather when Melchizedek met him.

So 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 about whom these things are said 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 said nothing concerning priests.