Numbers 3:40-51

40And Jehovah said unto 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 first-born 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 commanded him, all the first-born among the children of Israel. 43And all the first-born males according to the number of names, from a month old and upward, of those that were numbered of them, were twenty and two thousand two hundred and threescore and thirteen.

44And Jehovah spake unto Moses, saying, 45Take the Levites instead of all the first-born among the children of Israel, and the cattle of the Levites instead of their cattle; and the Levites shall be mine: I am Jehovah. 46And for the redemption of the two hundred and threescore and thirteen of the first-born of the children of Israel, that are over and above the number of the Levites, 47thou shalt take five shekels apiece by the poll; after the shekel of the sanctuary shalt thou take them (the shekel is twenty gerahs): 48and thou shalt give the money, wherewith the odd number of them is redeemed, unto Aaron and to his sons. 49And Moses took the redemption-money from them that were over and above them that were redeemed by the Levites; 50from the first-born of the children of Israel took he the money, a thousand three hundred and threescore and five shekels, after the shekel of the sanctuary: 51and Moses gave the redemption-money unto Aaron and to his sons, according to the word of Jehovah, as Jehovah commanded Moses.