Halakhah su Levitico 27:14

And this matter is similar to consecration (hekdesh). As we have found in the Torah that a person has the power to consecrate what is his, with the words of his mouth; and they will immediately be forbidden to him and to the whole world, as it is written (Leviticus 27:14), "And if a man consecrates his home to be holy." And so [too], does he have power over himself to forbid things upon his body. This is their, may their memory be blessed, always saying in the expressions of vows (Nedarim 15a), "Behold, it is upon me" - or (Nedarim 13b), "my mouth" for speech - meaning to say that he distances that thing from him. And he has the power to bind himself with a prohibition of that thing, [just] like he has the power to forbid his possessions. And that is itself the law and the reason why [only] an oath can rest upon something of substance [as well as] something that is not of substance (Nedarim 15b), since the oath lodges upon the body of the person, meaning to say that his body is obligated to do that thing - and behold, the body has substance. However a vow only rests upon something that has substance, as it is like him placing something into the category of other things that are forbidden; meaning to say that thing x will be forbidden to him like the category of the sacrifice that is forbidden to him. And if there is no substance to that which he is [literally] placing in the category, he has not done anything and it is nothing.

The commandment of appraising houses, such that he give the appraisal that the priest appraises and the addition of a fifth: To rule about the appraisals of homes; meaning [that] the priest appraise the house of one who consecrated it and wants to redeem it from that which is consecrated - he or his wife or his inheritors - and that [the redeemer] gives him according to the appraisal that he says to him, and also a fifth [of that sum]; as it is stated (Leviticus 27:14), "And if a man consecrates his house, holy, etc."