Leviticus 27:30-33

And all the tithe of the land, whether of the seed of the land, or of the fruit of the tree, is the LORD's: it is holy unto the LORD. And if a man will at all redeem ought of his tithes, he shall add thereto the fifth part thereof. 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. 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.