The Hebrew word NAZIR is today used for a monk, but the Torah has no place for such celibacy, and only the prophet Moses and certain true Tzaddikim were permitted to separate themselves from “the way of the world”. The Torah NAZIR was not one who separated himself from the world as a recluse from normal life. (On the contrary, the laws of NAZIR are bound up with family life: a man may make his son a NAZIR, he may invite his wife to take the vow of NAZIR, nullify her vow, etc.) The Nazirite vow is one that would in Temple times be taken on by a regular, normal person who did not want to separate himself from the entire world but did want to set extra limits on his own behavior over and above what the Torah requires of everyone.
Following on from the above-quoted Midrash — “Everybody who sees the damage done by and to the Sotah will want to abstain from wine, which is what brings to fornication” — the NAZIR living in the real world full of immorality wants to set for himself or herself extra personal boundaries against anything that may even lead to such immorality — wine and anything connected with wine, and even fancy hairstyles! The Nazirite may not defile himself with the dead, for while death exposes the folly of worship of the body, fears of aging and death often drive people to seek out the pleasures of the body compulsively.
The section dealing with the NAZIR sets forth the detailed laws of the Nazirite vow, yet implies that taking on specific vows is not encouraged by the Torah. Among his sacrifices the Nazirite has to bring a sin-offering for abstaining from permitted pleasures, as if what the Torah itself prohibits is not enough. When we take on vows, sometimes the tests become overwhelming, and may cause us to break them unwittingly (like the Nazirite who becomes unwittingly defiled by contact with the dead.).
What the Torah wants from us is the true labor of the heart: commitment. A vow is an explicit verbal commitment that we make, creating a Torah of our own, something that goes beyond the letter of the law. It may be in the form of a personal boundary. It may be in the form of a specific commitment. Jacob, the founding father of Israel, builder of the home, was the first one to make a vow. At Mount Moriah, the Temple Mount where Jacob dreamed of the ladder (SULAM = SINAI = Giving of the Torah), he woke up and set up the Temple foundation and vowed to give a tithe of all he received to G-d. The Torah that came forth from the Sanctuary (Leviticus 1:1) begins with a vow — that of a person who wants to offer a sacrifice in the Temple: “When a person would offer an offering” (Leviticus 1:2).
The Nazirite vow is much more demanding than a one-time sacrifice: it is a commitment to a very strict discipline — complete abstinence from grapes and wine, no haircutting to emphasize the opposite of body-oriented immorality, etc. In the present day world in which we lead our lives, the actual Nazirite vow is not a practical possibility, but we certainly all know ways in which it is desirable to hedge ourselves in with personal boundaries that help separate ourselves from that which is negative and evil in this world of Good and Evil.
What is asked of us is to make our personal boundaries and adhere to them without expressing them in the form of specific vows. The danger of the vow is that during the initial enthusiasm in which in which it is made, we may not see prospective difficulties that could make it impossible to adhere to it. What is asked of us is not to tie ourselves up in verbal commitments that we cannot keep, but rather, to make an inner commitment — the commitment of the heart — to what we know to be good, and then do everything in our power to adhere to our commitment.