Leviticus 27:9-13

The case of cattle

Such an animal, when presented as a vow, must not be changed, a bad for a good. Otherwise both animals became dedicated. If the animal so presented was -unclean," and as such could not lawfully be offered to God, the priest was to set upon it a value in proportion to its worth, whereupon the owner might sell it for that sum and pay over the amount. If, however, he desired to have it back, he must pay in addition one-fifth of the price which the priest had adjudged.