Leviticus 27:26-27

‘But the firstborn of the animals, which should be the LORD’s firstborn, no man shall dedicate; whether it is an ox or sheep, it is the LORD’s. And if it is an unclean animal, then he shall redeem it according to your valuation, and shall add one-fifth to it; or if it is not redeemed, then it shall be sold according to your valuation.