Numbers 3:12 WEB

¹⁰  You shall appoint Aaron and his sons, and they shall keep their priesthood. The stranger who comes near shall be put to death.'

¹¹  Yahweh spoke to Moses, saying,

¹²  'Behold, I have taken the Levites from among the children of Israel instead of all the firstborn who open the womb among the children of Israel; and the Levites shall be mine:

¹³  for all the firstborn are mine. On the day that I struck down all the firstborn in the land of Egypt I made holy to me all the firstborn in Israel, both man and animal. They shall be mine. I am Yahweh.'

¹⁴  Yahweh spoke to Moses in the wilderness of Sinai, saying,