Numbers 3:41-45

Take the Levites for me instead of the firstborn sons of Israel; take the animals of the Levites instead of the firstborn animals from the rest of Israel. I am the LORD.” So Moses did what the LORD commanded and counted all the firstborn sons of the Israelites. When he listed all the firstborn sons one month old or older, there were 22,273 names. The LORD also said to Moses, “Take the Levites instead of all the firstborn sons of the Israelites, and take the animals of the Levites instead of the animals of the other people. The Levites are mine. I am the LORD.