Leviticus 27:32-34

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

³³He shall not inquire whether it be good or bad, neither shall he change it; and if he change it at all, then both it and that for which it is changed 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.