Números 18:15

15 The first offspring of every womb, both human and animal, that is offered to the Lord is yours. But you must redeem every firstborn son and every firstborn male of unclean animals.

15 Everything that openeth the womb, of all flesh which they offer unto Jehovah, both of man and beast shall be thine: nevertheless the first-born of man shalt thou surely redeem, and the firstling of unclean beasts shalt thou redeem.