Numbers 3:10 YLT

⁸  and they have kept all the vessels of the tent of meeting, and the charge of the sons of Israel, to do the service of the tabernacle;

⁹  and thou hast given the Levites to Aaron and to his sons; they are surely given to him out of the sons of Israel.

¹⁰  'And Aaron and his sons thou dost appoint, and they have kept their priesthood, and the stranger who cometh near is put to death.'

¹¹  And Jehovah speaketh unto Moses, saying,

¹²  'And I, lo, I have taken the Levites from the midst of the sons of Israel instead of every first-born opening a womb among the sons of Israel, and the Levites have been Mine;