This redemption money (see the marginal references) would perhaps be exacted from the parents of the “youngest” children of the 22,273 Numbers 3:43. The cattle of the Levites was doubtless taken in the gross as an equivalent for the first-born cattle of the other tribes, which of course, no less than the first-born of men, belonged to the Lord; and in future would have to be redeemed Numbers 18:15; Deuteronomy 15:19.
Numbers 3:44-51
44 And the LORD spake unto Moses, saying,
45 Take 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 the LORD.
46 And for those that are to be redeemed of the two hundred and threescore and thirteen of the firstborn of the children of Israel, which are more than the Levites;
47 Thou shalt even take five shekels apiece by the poll, after the shekel of the sanctuary shalt thou take them: (the shekel is twenty gerahs:)
48 And thou shalt give the money, wherewith the odd number of them is to be redeemed, unto Aaron and to his sons.
49 And Moses took the redemption money of them that were over and above them that were redeemed by the Levites:
50 Of the firstborn of the children of Israel took he the money; a thousand three hundred and threescore and five shekels, after the shekel of the sanctuary:
51 And Moses gave the money of them that were redeemed unto Aaron and to his sons, according to the word of the LORD, as the LORD commanded Moses.