Numbers 3:12, 41, 45

“Behold, I 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

And you shall take the Levites for me—I am the LORD—instead of all the firstborn among the people of Israel, and the cattle of the Levites instead of all the firstborn among the cattle of the people of Israel.”

“Take the Levites instead of all the firstborn among the people of Israel, and the cattle of the Levites instead of their cattle. The Levites shall be mine: I am the LORD.