Numbers 3:45

“And you shall redeem with a lamb the first offspring from a donkey; and if you do not redeem it, then you shall break its neck. You shall redeem all the firstborn of your sons. None shall appear before Me empty-handed.

“Now, behold, I have taken the Levites from among the sons of Israel instead of every firstborn, the first offspring of the womb among the sons of Israel. So the Levites shall be Mine.

“And you shall take the Levites for Me, I am Yahweh, 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.”

for they are wholly given to Me from among the sons of Israel. I have taken them for Myself instead of every first issue of the womb, the firstborn of all the sons of Israel.

“And behold, I Myself have taken your brothers the Levites from among the sons of Israel; they are a gift to you, given to Yahweh, to perform the service for the tent of meeting.

“Then you will know that I have sent this commandment to you, that My covenant may continue with Levi,” says Yahweh of hosts.