Leviticus 27:26-27 - Redemption Of The Firstborn
26 A firstborn animal already belongs to Jehovah because it was born first. Therefore, it cannot be set apart as holy. Whether it is a bull or a sheep, it belongs to Jehovah. 27 If it is an unclean animal it must be bought back. The payment will be its full value plus one-fifth more. If it is not bought back, it must be sold at the value given it.
40 Jehovah said to Moses: Register every firstborn male of the Israelites who is at least one month old, and make a list of their names. 41 I am Jehovah. Take the Levites for me to be substitutes for all firstborn Israelites. Also take the animals of the Levites to be substitutes for all firstborn animals of the Israelites. 42 Moses registered all the firstborn Israelites as Jehovah commanded him. 43 The total of all the firstborn males at least one month old was twenty-two thousand two hundred and seventy three. They were listed by name.
44 Jehovah said to Moses: 45 Take the Levites to be substitutes for all the firstborn Israelites and the animals of the Levites to be substitutes for their animals. The Levites will be mine. I am Jehovah.
46 There are two hundred and seventy-three more firstborn male Israelites than there are Levites. 47 It will cost you two ounces of silver per person, using the standard weight of the holy place, to buy them back. 48 Give the silver to Aaron and his sons. It will buy back those Israelites who outnumber the Levites.
49 Moses took this ransom money from the Israelites who outnumbered the Levites. 50 The silver Moses collected for the firstborn Israelites weighed thirty-four pounds using the standard weight of the holy place. 51 Then Moses did what Jehovah said and gave Aaron and his sons this ransom money as he had been commanded.