Leviticus 27:26-27

26 But a a firstborn of animals, which as a firstborn belongs to the  Lord, no man may dedicate; whether ox or sheep, it is the  Lord’s. 27 And if it is an unclean animal, then he shall buy it back at the valuation, b and add a fifth to it; or, if it is not redeemed, it shall be sold at the valuation.

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