5 And even those of the sons of Levi who attain the priesthood have command according to the Law to take a tenth from the people, their own brethren, although these have sprung from the loins of Abraham.
Hebrews 7:5 Cross References - Riverside
Hebrews 5:4
4 And no one takes this honor upon himself unless called by God, as Aaron was.
Hebrews 7:10
10 For he was still in the loins of his father when Melchizedek met Abraham.