Leviticus 27:9

If it be a beast it shall be holy, &c. A second sort of things vowed to God are beasts. With respect to which the law is, that the very individual beast was to be disposed of by the owner according to the first intention of his vow, whether to be sacrificed upon the altar, or given to the priests, or sold for the use of the sanctuary, the price to be applied to the repairs of the house of God, or to purchase the usual sacrifices. This is what we are to understand by its being holy, as appears from Leviticus 27:10. The design of this law was to preserve a reverence toward things once consecrated, that they might not return to common uses.