Numbers 3:10-12

Young's Literal Translation

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;