Numbers 3:40-45

40And Jehovah said to Moses, Number all the first-born males of the children of Israel from a month old and upward, and take the number of their names.

41And thou shalt take the Levites for me (I am Jehovah) instead of all the firstborn among the children of Israel; and the cattle of the Levites, instead of all the firstlings among the cattle of the children of Israel.

42And Moses numbered, as Jehovah had commanded him, all the firstborn among the children of Israel.

43And all the firstborn males, by the number of the names, from a month old and upward, according to their numbering, were twenty-two thousand two hundred and seventy-three.

44And Jehovah spoke to Moses, saying,

45Take the Levites instead of all the firstborn among the children of Israel, and the cattle of the Levites instead of their cattle; and the Levites shall be mine: I am Jehovah.