Hebrews 7:5-9

5Now the law commands the sons of Levi who become priests to collect a tenth from the people—that is, from their brothers—though they too are descended from Abraham. 6But Melchizedek, who did not trace his descent from Levi, collected a tenth from Abraham and blessed him who had the promises. 7And indisputably, the lesser is blessed by the greater.

8In the case of the Levites, mortal men collect the tenth; but in the case of Melchizedek, it is affirmed that he lives on. 9And so to speak, Levi, who collects the tenth, paid the tenth through Abraham.