Numbers 3:40-41

40Then the Lord said to Moses, “1Number every firstborn male of the sons of Israel from a month old and upward, and 2make a list of their names.

41You 3shall take the Levites for Me, I am the Lord, instead of all the firstborn among the sons of Israel, and the cattle of the Levites instead of all the firstborn among the cattle of the sons of Israel.”