Leviticus 27:26-27

BSB(i) 26 But no one may consecrate a firstborn of the livestock, because a firstborn belongs to the LORD. Whether it is an ox or a sheep, it is the LORD’s. 27 But if it is among the unclean animals, then he may redeem it according to your valuation and add a fifth of its value. If it is not redeemed, then it shall be sold according to your valuation.