Leviticus 27:2

Speak unto the children of Israel and say unto them, When a man shall make a singular vow, an exceptional, unusual, special promise to the Lord, which involved the offering of his own body to the Lord for some service in His worship, the persons shall be for the Lord by thy estimation; the redemption from the obligations of the promise had to be made in accordance with the estimate given out, first by Moses and later by the priest in charge. The fulfillment of the vow consisted in this, that the person concerned paid the price of the estimation to the Sanctuary.