“When a man shall clearly utter a vow of persons to Hashem, according to your valuation.” (Vayikra 27:2)
It is a positive commandment one must judge according to the valuations of people. This refers to the instance when a person says “My value is upon me!” or “So and so’s value is upon me!”, that he must give the Kohein the value that he promised; not more and not less. It is all according to the amounts specified in the verses, with the differences between man and woman and the different age groups, as it says in the verse, “When a man shall clearly utter a vow of persons to Hashem, according to your valuation.”. These valuations are included in the area of vows to Hekdesh (Holy property), and one is prohibited from breaking the vow with two prohibitions; that of “He must not break his word!”, and that of “You may not delay in its fulfillment!”, as well as transgressing the positive commandment of “He must do all that came out of his mouth!”
Amongst the roots of this commandment are that since a person can only connect with the upper regions with speech, which is the most honored part of man, and is called the “living soul” of the person (as Onkelos translates “And it was in the man as a speaking soul!”), for the rest of the body are considered to be dead, and if a person would lose this good part, he will remain like a dead body and a vessel which no one wants. Because of all of the above, we are commanded to fulfil every utterance for heavenly purposes. Examples of this are sanctification of property and giving charity. Even in worldly matters, where there are no explicit commandments, the rabbis gave many warnings about a person not breaking their word.
This commandment applies in all places and at all times, both to men and to women. Chazal nevertheless said that ideally one should not promise peoples values nowadays. One who promised a person’s value and did not keep his promise has transgressed this commandment.