Leviticus 27:9-13

9‘Now if it is an animal of the kind that 1one can present as an offering to the Lord, any such animal that one gives to the Lord shall be holy. 102He shall not replace it nor exchange it, a good for a bad, or a bad for a good; yet if he does exchange animal for animal, then both it and its substitute shall become holy. 11If, however, it is any unclean animal of the kind which 3one does not present as an offering to the Lord, then he shall place the animal before the priest. 12And the priest shall assess it 4as either good or bad; as you, the priest, assess it, so shall it be. 13But if he should ever want to redeem it, then he shall add a fifth of it to your assessment.