Leviticus 27:25-27

King James Version

²⁵ And all thy estimations shall be according to the shekel of the sanctuary: twenty gerahs shall be the shekel.

²⁶ Only the firstling of the beasts, which should be the Lord's firstling, no man shall sanctify it; whether it be ox, or sheep: it is the Lord's.

²⁷ And if it be of an unclean beast, then he shall redeem it according to thine estimation, and shall add a fifth part of it thereto: or if it be not redeemed, then it shall be sold according to thy estimation.