Leviticus 27:17

If he sanctify his field from the year of jubile, according to thy estimation it shall stand.

The verse belongs to the law governing the sanctifying of a man's substance to the Lord. A field sanctified from the year of jubile stands according to the estimation placed upon it, which is the priest's estimation of its value. One who sanctified it and would keep it, or who chooses to exchange or redeem what he sanctified, must pay that estimation with an added fifth added to it. What has been sanctified is sacred to God and the vow is binding, so it cannot be taken back with no equivalent given. The chapter's rule of valuation and redemption also covers a singular vow concerning a member of the household, who could be redeemed according to the priest's estimation. Applied in this way, the vow concerning Jephthah's daughter devoted her to the Lord's service in perpetual virginity rather than as a sacrifice.