Leviticus 27:30-33

30“ ‘A tithe of everything from the land, whether grain from the soil or fruit from the trees, belongs to the Lord; it is holy to the Lord. 31Whoever would redeem any of their tithe must add a fifth of the value to it. 32Every tithe of the herd and flock—every tenth animal that passes under the shepherd’s rod—will be holy to the Lord. 33No one may pick out the good from the bad or make any substitution. If anyone does make a substitution, both the animal and its substitute become holy and cannot be redeemed.’ ”