G2405–ἱερατεία–hierateia

according to the custom of the priesthood, his lot was to make perfume, having gone into the sanctuary of the Lord,

ἱερατείας hi'erateias “priesthood”

and those, indeed, out of the sons of Levi receiving the priesthood, a command have to take tithes from the people according to the law, that is, their brethren, even though they came forth out of the loins of Abraham;

ἱερατείαν hi'erateian “priestly office”