Leviticus 27:33 KJV
He 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.
Leviticus 27:33, King James Version
In context
32 And 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.
33 He 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.
34 These are the commandments, which the Lord commanded Moses for the children of Israel in mount Sinai.