Num 3:40 And the LORD said to Moses, “List all the firstborn males of the people of Israel, from a month old and upward, taking the number of their names. And you shall take the Levites for me—I am the LORD—instead of all the firstborn among the people of Israel, and the cattle of the Levites instead of all the firstborn among the cattle of the people of Israel.” So Moses listed all the firstborn among the people of Israel, as the LORD commanded him. And all the firstborn males, according to the number of names, from a month old and upward as listed were 22,273. And the LORD spoke to Moses, saying, “Take the Levites instead of all the firstborn among the people of Israel, and the cattle of the Levites instead of their cattle. The Levites shall be mine: I am the LORD. And as the redemption price for the 273 of the firstborn of the people of Israel, over and above the number of the male Levites, you shall take five shekels per head; you shall take them according to the shekel of the sanctuary (the shekel of twenty gerahs), and give the money to Aaron and his sons as the redemption price for those who are over.” So Moses took the redemption money from those who were over and above those redeemed by the Levites. From the firstborn of the people of Israel he took the money, 1,365 shekels, by the shekel of the sanctuary. And Moses gave the redemption money to Aaron and his sons, according to the word of the LORD, as the LORD commanded Moses.
Number all the first-born of the males of the children of Israel, &c.—The principle on which the enumeration of the Levites had been made was now to be applied to the other tribes. The number of their male children, from a month old and upward, was to be reckoned, in order that a comparison might be instituted with that of the Levites, for the formal adoption of the latter as substitutes for the first-born. The Levites, amounting to twenty-two thousand, were given in exchange for an equal number of the first-born from the other tribes, leaving an excess of two hundred seventy-three; and as there were no substitutes for these, they were redeemed at the rate of five shekels for each (Nu 18:15, 16). Every Israelite would naturally wish that his son might be redeemed by a Levite without the payment of this tax, and yet some would have to incur the expense, for there were not Levites enough to make an equal exchange. Jewish writers say the matter was determined by lot, in this manner: Moses put into an urn twenty-two thousand pieces of parchment, on each of which he wrote “a son of Levi,” and two hundred seventy-three more, containing the words, “five shekels.” These being shaken, he ordered each of the first-born to put in his hand and take out a slip. If it contained the first inscription, the boy was redeemed by a Levite; if the latter, the parent had to pay. The ransom-money, which, reckoning the shekel at half a crown, would amount to 12s. 6d. each, was appropriated to the use of the sanctuary. (Brown)
The number of firstborn sons is low if accounted for all the nation; it would mean that only one in 27 sons were firstborns – an unlikely percentage. It is more probable that the 22,273 firstborn sons were those born in the thirteen months since their departure from Egypt. “The price for the redemption of the excess firstborn of the Israelites was five shekels, or about 2.1 ounces of silver per person. The Israelites not covered by a Levite were redeemed with a silver shekel, but under the New Covenant the believer is redeemed with something far more costly and precious: the blood of Jesus Christ, as a lamb without blemish. (Guzik)
God said, “the firstborn are Mine”. The firstborn of the Israelites and of their flocks were for special service and use by God. This at first glance seems a bit strange when we consider “All” is God’s. Yet here we have God calling out the firstborn for special service. In His plan and purpose, God, ordained a redemption of the Israelites firstborn by a Levite. God ordains and gives His redeemed children gifts and talents for His service, honor and glory.