Leviticus 27:26-27 - Redemption Of The Firstborn
26 However, the first-born of an animal, which should be Jehovah's first-born, no man shall sanctify it, whether an ox, or sheep, it is Jehovah's. 27 And if it is of an unclean animal, then he shall redeem it according to your estimation, and shall add a fifth part of it to it. Or if it is not redeemed, then it shall be sold according to your estimation.
40 And Jehovah said to Moses, Number all the first-born of the males of the sons of Israel from a month old and upward, and take the number of their names. 41 You shall take the Levites for Me, I am Jehovah, in the place of all the first-born among the sons of Israel; and the cattle of the Levites instead of all the firstlings among the cattle of the sons of Israel. 42 And as Jehovah commanded him, Moses numbered all the first-born among the sons of Israel. 43 And all the first-born males by the number of names, from a month old and upward, of those numbered of them, were twenty-two thousand two hundred and seventy-three.
44 And Jehovah spoke to Moses saying, 45 Take the Levites instead of all the first-born among the sons of Israel, and the cattle of the Levites instead of their cattle. And the Levites shall be Mine. I am Jehovah.
46 And for those that are to be redeemed of the two hundred and seventy-three of the first-born of the sons of Israel, who are more than the Levites, 47 you shall even take five shekels each by the head, according to the shekel of the sanctuary you shall take. (The shekel is twenty gerahs.) 48 And you shall give to Aaron, and to his sons, the silver of the redeemed left over among them.
49 And Moses took the redemption silver from those who were over and above the ones who were redeemed by the Levites. 50 He took the silver from the first-born of the sons of Israel: one thousand three hundred and sixty-five shekels, according to the shekel of the sanctuary. 51 And Moses gave the silver from those who were redeemed to Aaron and to his sons, according to the word of Jehovah, as Jehovah commanded Moses.