Hebrews 7:5-9

7:5 And those of the sons of Levi who receive the priestly office have authorization according to the law to collect a tithe from the people, that is, from their fellow countrymen, although they too are descendants of Abraham. 7:6 But Melchizedek who does not share their ancestry collected a tithe from Abraham and blessed the one who possessed the promise. 7:7 Now without dispute the inferior is blessed by the superior, 7:8 and in one case tithes are received by mortal men, while in the other by him who is affirmed to be alive. 7:9 And it could be said that Levi himself, who receives tithes, paid a tithe through Abraham.