Leviticus 27:32-34

³²And concerning the tithe of the herd, or of the flock, even of whatsoever passeth under the rod, the tenth shall be holy unto the LORD.

³³He shall not search whether it be good or bad, neither shall he change it: and if he change it at all, then both it and the change thereof shall be holy; it shall not be redeemed.

³⁴These are the commandments, which the LORD commanded Moses for the children of Israel in mount Sinai.