Leviticus 27:32-34

³²All the tithe of the herds or the flocks, whatever passes under the rod, the tenth shall be holy to the LORD.

³³He shall not examine whether it is good or bad, neither shall he exchange it. If he exchanges it at all, then both it and that for which it is exchanged shall be holy. It shall not be redeemed.’”

³⁴These are the commandments which the LORD commanded Moses for the children of Israel on Mount Sinai.