Leviticus 27:30-33

“All the tithe of the land whether from the seed of the land, or the fruit of the trees, belongs to ADONAI, for it is holy to ADONAI. If a man redeems anything of his tithe he must add a fifth part to it. From all the tithe of the herds or the flocks, whatever passes under the rod, a tenth will be holy to ADONAI. One is not to inquire if it is good or bad, nor exchange it. Or if he does exchange it, then both it and that for which it is exchanged will become holy, and may not be redeemed.”