Leviticus 27:26-28

Amplified Bible, Classic Edition

²⁶ But the firstling of the animals, since a firstling belongs to the Lord, no man may dedicate, whether it be ox or sheep. It is the Lord’s [already].

²⁷ If it be of an unclean animal, the owner may redeem it according to your valuation, and shall add a fifth to it; or if it is not redeemed, then it shall be sold according to your valuation.

²⁸ But nothing that a man shall devote to the Lord of all that he has, whether of man or beast or of the field of his possession, shall be sold or redeemed; every devoted thing is most holy to the Lord.