Leviticus 27:4

And if it be a female, then thy estimation shall be thirty shekels.

Leviticus 27 belongs to the law concerning things promised to God, providing the priest's estimation of the value of a person included in a special vow in Leviticus 27:2-8. Within that law the valuation of a female, in the age group covered by the surrounding rules, is set at thirty shekels of silver. What is vowed becomes sacred, so that if a person wanted to keep vowed property such as land or a house, the priest valued it and the person had to add one fifth to that value. That added amount made the vow binding and reminded of the sacredness of what had been consecrated to God.

A dedicated person was not to be sacrificed or put to other use, but could be represented, released, or redeemed by payment of the prescribed valuation into the treasury of the Lord's house rather than offering the person as a sacrifice. This establishes the principle that when a vow involved something unlawful to offer, its value could be estimated and given instead, so a person could not lawfully be offered as a burnt offering. The regulations are therefore relevant to whether Jephthah could have been released from his vow by paying the prescribed valuation.

Because Jephthah did not redeem his daughter, his vow is understood not as sacrificing her but as dedicating her to the Lord's service as a perpetual virgin, which the law allowed.