And thou shalt give the Levites unto Aaron and to his sons: they are wholly given unto him out of the children of Israel.
Numbers 8:19
'And I give the Levites gifts to Aaron and to his sons, from the midst of the sons of Israel, to do the service of the sons of Israel in the tent of meeting, and to make atonement for the sons of Israel, and there is no plague among the sons of Israel in the sons of Israel's drawing nigh unto the sanctuary.'
'And I, lo, I have taken your brethren the Levites from the midst of the sons of Israel; to you a gift they are given by Jehovah, to do the service of the tent of meeting;
and thou, and thy sons with thee, do keep your priesthood, for everything of the altar, and within the vail, and ye have served; a service of gift I make your priesthood; and the stranger who is coming near is put to death.'