Leviticus 27:26-27

“ ‘No one, however, may dedicate the firstborn of an animal, since the firstborn already belongs to the LORD; whether an ox or a sheep, it is the LORD’s. If it is one of the unclean animals, it may be bought back at its set value, adding a fifth of the value to it. If it is not redeemed, it is to be sold at its set value.