Hebrews 7:4-11

Now observe how great this man was to whom Abraham, the patriarch, gave a tenth of the choicest spoils. And those indeed of the sons of Levi who receive the priest’s office have commandment in the Law to collect a tenth from the people, that is, from their brethren, although these are descended from Abraham. But the one whose genealogy is not traced from them collected a tenth from Abraham and blessed the one who had the promises. But without any dispute the lesser is blessed by the greater. In this case mortal men receive tithes, but in that case one receives them, of whom it is witnessed that he lives on. And, so to speak, through Abraham even Levi, who received tithes, paid tithes, for he was still in the loins of his father when Melchizedek met him. 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?