Leviticus 27:30-33

VIN(i) 30 And all the tenth of the land from the seed of the land, from the fruit of the tree, is to the LORD: it is holy to the LORD. 31 If a man redeems anything of his tithe, he shall add a fifth part to it. 32 And all the tithe of the herd and of the flock, all that passes under the rod, a tenth shall be holy to the LORD; 33 "'You must not look to see if it is good or bad or exchange it. If you do exchange it, both the first animal and its substitute will be holy. They may not be bought back.'"