Shall make a singular vow. — Better, shall consecrate a vow. (See Leviticus 22:21.) According to the interpretation of this phrase which obtained during the second Temple it denotes shall pronounce a vow. Hence the ancient Chaldee Versions render it, “shall distinctly pronounce a vow.” Accordingly, no vow mentally made or conceived was deemed binding. It had to be distinctly pronounced in words. The form of the vow is nowhere given in the Bible. Like many other points of detail, the wording of it was left to the administrators of the law. They divided vows into two classes: (1) Positive vows, by which a man bound himself to consecrate for religious purposes his own person, those members of his family over whom he had control, or any portion of his property, and for this kind of vow the formula was “Behold I consecrate this to the Lord”; and (2) Negative vows, by which he promised to abstain from enjoying a certain thing, for which the formula was, “Such and such a thing be unlawful to me for so many days, weeks, or for ever.”
The persons shall be for the Lord by thy estimation. — Better, souls to the Lord according to thy estimation., that is, the vow consists of consecrating persons to the Lord with the intention of redeeming by money the persons thus consecrated, according to the valuation put upon them by Moses. This part of the verse explains the nature of the vow, and takes it for granted that by consecrating a human being to God by a vow is meant to substitute the money value for him. By the suffix, “thy estimation,” Moses is meant, to whom these regulations are here Divinely communicated, and upon whom it devolved in the first instance to carry out the law. (See Leviticus 5:15; Leviticus 5:18.) During the second Temple any Israelite could estimate the money value of a person thus vowed to the Lord.