Hebrews 7:5
"And verily they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham:"
Cross References (ranked by relevance)
Therefore thou and thy sons with thee shall keep your priest’s office for everything of the altar, and within the vail; and ye shall serve: I have given your priest’s office unto you as a service of gift: and the stranger that cometh nigh shall be put to death.
Nevertheless thou shalt not build the house; but thy son that shall come forth out of thy loins, he shall build the house unto my name.
For he was yet in the loins of his father, when Melchisedec met him.
And I perceived that the portions of the Levites had not been given them: for the Levites and the singers, that did the work, were fled every one to his field.
All the souls that came with Jacob into Egypt, which came out of his loins, besides Jacob’s sons’ wives, all the souls were threescore and six;
And take thou unto thee Aaron thy brother, and his sons with him, from among the children of Israel, that he may minister unto me in the priest’s office, even Aaron, Nadab and Abihu, Eleazar and Ithamar, Aaron’s sons.