Hebrews 7:4-6

7:4 But see how great he must be, if Abraham the patriarch gave him a tithe of his plunder. 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.