Hebrews 7:8-12

8and in one case tithes are received by mortal men, while in the other by him who is affirmed to be alive.

9And it could be said that Levi himself, who receives tithes, paid a tithe through Abraham.

10For he was still in his ancestor Abraham’s loins when Melchizedek met him.

11So if perfection had in fact been possible through the Levitical priesthood – for on that basis the people received the law – what further need would there have been for another priest to arise, said to be in the order of Melchizedek and not in Aaron’s order?

12For when the priesthood changes, a change in the law must come as well.