Leviticus 27:2 - Wesley's Explanatory Notes

A singular vow — Or, an eminent, or hard vow, not concerning things, which was customary, but concerning persons, which he devoted to the Lord, which was unusual and difficult: yet there want not instances of persons who devoted either themselves or their children, and that either more strictly, as the Nazarites, and the Levites, 1 Samuel 1:11, and for these there was no redemption admitted, but they were in person to perform the service to which they were devoted: or more largely, as some who were not Levites, might yet through zeal to God, or to obtain God's help, which they wanted or desired, devote themselves or their children to the service of God and of the sanctuary, tho' not in such a way as the Levites, which was forbidden, yet in some kind of subserviency to them. And because there might be too great a number of persons thus dedicated, which might be burdensome to the sanctuary, an exchange is allowed, and the priests are directed to receive a tax for their redemption. By thy estimation — Thine, O man that vowest, as appears from Leviticus 27:8, where his estimation is opposed to the priest's valuation. Nor was there any fear of his partiality in his own cause, for the price is particularly limited. But where the price is undetermined, there, to avoid that inconvenience, the priest is to value it, as Leviticus 27:8, Leviticus 27:12.