Hebrews 7:4–10

[4] See how great this man was to whom Abraham the patriarch gave a tenth of the spoils! [5] And those descendants of Levi who receive the priestly office have a commandment in the law to take tithes from the people, that is, from their brothers, though these also are descended from Abraham. [6] But this man who does not have his descent from them received tithes from Abraham and blessed him who had the promises. [7] It is beyond dispute that the inferior is blessed by the superior. [8] In the one case tithes are received by mortal men, but in the other case, by one of whom it is testified that he lives. [9] One might even say that Levi himself, who receives tithes, paid tithes through Abraham, [10] for he was still in the loins of his ancestor when Melchizedek met him. (ESV)