Hebrews 7:4-6

Living_Oracles(i) 4 Now, consider how great this priest was, to whom even Abraham, the patriarch, gave a tenth of the spoils. 5 For they, indeed, of the sons of Levi, who received the priesthood, have a commandment to tithe people according to the law; that is, their brethren, although they have come forth from the loins of Abraham: 6 but he, who did not derive his pedigree from their progenitors, tithed Abraham, and blessed the holder of the promises.