Hebrews 7:5; Hebrews 7:10

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:

10 For he was yet in the loins of his father, when Melchisedec met him.