9 And thou shalt give the Levites unto Aaron and to his sons; they are completely given unto him out of the sons of Israel.
10 And thou shalt appoint Aaron and his sons that they shall guard their priesthood; and the stranger that comes near shall be put to death.
11 And the Lord spoke unto Moses, saying,
12 Behold, I have taken the Levites from among the sons of Israel instead of all the firstborn that open the womb among the sons of Israel; therefore the Levites shall be mine;
13 because all the firstborn are mine; from the day that I smote all the firstborn in the land of Egypt, I sanctified unto me all the firstborn in Israel, both of men and of animals; they shall be mine: I am the Lord.
14 The Lord also spoke unto Moses in the wilderness of Sinai, saying,
15 Number the sons of Levi by the houses of their fathers, by their families; thou shalt number every male from a month old and upward.