Numbers 3:41-45

41And you 1shall 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 in place of all the firstborn among the cattle of the sons of Israel.” 42So Moses counted all the firstborn among the sons of Israel, just as the Lord had commanded him; 43and all the firstborn males, by the number of names from a month old and upward for their numbered men, were 222,273.

44Then the Lord spoke to Moses, saying, 45“3Take the Levites in place of all the firstborn among the sons of Israel, and the cattle of the Levites in place of their cattle. And the Levites shall be Mine; I am the Lord.