Numbers 3:12
12 “Behold, nI have taken the Levites from among the people of Israel instead of every firstborn who opens the womb among the people of Israel. The Levites shall be mine,
Numbers 3:13
13 for oall the firstborn are mine. pOn the day that I struck down all the firstborn in the land of Egypt, I consecrated for my own all the firstborn in Israel, both of man and of beast. They shall be mine: I am the Lord.”
Numbers 3:16–18
16 So Moses listed them according to the word of the Lord, as he was commanded. 17 rAnd these were the sons of Levi by their names: Gershon and Kohath and Merari. 18 And these are the names of the sons of Gershon by their clans: sLibni and Shimei.