In Moses' day, a personal vow was as binding as a written contract. It was one thing to say you would do something, but it was considered much more serious when you made a solemn vow to do it. God instituted the Nazirite vow for people who wanted to devote some time exclusively to serving him. This vow could be taken for as little as 30 days or as long as a lifetime. It was voluntary, with one exception - parents could take the vow for their young children, making them Nazirites for life. (The Life Application Study Bible - Zondervan)
   The term "fermented drink" (shekar) is often used in association with "wine" (yayin) and is found in texts condemning drunkenness (see 1st Samuel 1:15; Proverbs 20:1; Isaiah 5:11, 22; et al.). But shekar is also used in other texts describing the normal, moderate drinking (along with wine) that was part of the expected common food of the people of Israel. Further, shekar could be used in the drink offering (Numbers 28:7) in the worship of the Lord. Since yayin is the fermented product of the vine, presumably shekar is the fermented product of the field, i.e., beer. The Nazirite was to abstain from both wine and beer and from everything associated with the wine grape, not just the fermented beverages, but even the vinegar that results when such products sour. Moreover, the prohibition included fresh grape juice, grapes either fresh or dried, and even the seed and skin of the grape. It is unclear why grape products are specifically forbidden to the Nazirite.

   A second voluntary prohibition for the Nazirite was the normal and expected trimming of the hair (cross-reference Judges 13:5). The unexpectedly long hair of a Nazirite man was a physical mark of his vow of special "separation" to the Lord. Since women in most cultures wear their hair longer than men do, presumably the Nazirite woman might not only have let her hair grow long but may have allowed it to remain relatively unkempt (cross-reference "untended vines," Leviticus 25:5, 11), or perhaps she let it hang loose as opposed to putting it up. Otherwise, it is difficult to see how the (unusually) long hair of a woman would be a distinctive sign of her period of vow. In this way, the Nazirite was to be "holy."

   The third prohibition for the Nazirite concerned any physical contact with a dead body - even within his own family. Here a person faced heart-rending decisions not to do normal things in times of great grief because of intense consecration to the Lord. Even a priest was expected to care for the dead body of a close relative (Leviticus 21:1-3). But the Nazirite could not care for such a body, no matter how beloved the person, or he would bring contamination on himself.

   The accidental death of a person in the proximity of the Nazirite makes him unclean, guilty of sin before the Lord. This section deals with the unexpected and the unplanned events of daily living. The special focus of the person's contamination is his dedicated hair, which was to be shaved on the seventh day of the Nazirite's rite of purification. Then, following obligatory offerings of birds (the less expensive offerings) for sin (verse 8) and burnt offerings and a lamb (the more expensive) for guilt offerings, the person would rededicate himself to the Lord for the period of time that had originally been planned; the time spent up to that point would no longer count because of the contamination. No wonder this vow is termed a "hard vow" (verse 2; cross-reference Proverbs 20:25).

   The public presentation of the Nazirite by the priest at the Tent of Meeting before the Lord shows that this type of vow was not just an intensely personal and private act of relationship with the Lord. Any such public rite suggests that the vow was also a matter of public knowledge. Presumably, the community could be supportive of the person during the time of his vow. But more important is the personal presentation before the Lord at the Tent of Meeting (see verses 13-14, 16-17, 20). Through this vow, one had a profound sense of one's coming into the presence of the Holy One.

   Burning the hair signified the completion of the vow and demonstrated that the act of the Nazirite was in devotion to the Lord. Since the Nazirite was prohibited any contact whatsoever with wine and vine products during his vow, one might conclude that such things are essentially evil in themselves. However, a wine offering ("drink offering") was presented on the altar to the Lord along with the clean animals and the associated grain offerings. The conclusion respecting the prohibition of wine and beer to the Nazirite during his vow must take into account the use of wine in the rite of vow-completion as well as the notice that he was then free to drink wine again (verse 20).

   The costs of the Nazirite vow were considerable and varied. It was not a demand of God on his people but a provision for men or women to voluntarily show their devotion to him.

   The words of the prayer of verses 24-26 are termed the Aaronic Benediction. Perhaps the most impressive aspect of this prayer is that it is a provision for God's desire to bless his people. Blessing is his idea. It is not something his people must beg for, but the out-reaching of his grace.
   The pattern of the prayer is exquisite; the language is poetic and emotive. There are three lines each with the divine name "Lord"; the repetition of the divine name gives force to the expression of verse 27 and is certainly fitting with the (later) Christian revelation of the Trinity. Each line conveys two elements of benediction, and the lines are progressively longer. Not counting the threefold use of the divine name, there are twelve words to the prayer, which suggest the twelve tribes of Israel.
   This prayer speaks of the light of the presence of the Lord; but there is a sense that the prayer itself is light-giving. Prayed in faith, it expects God to respond by drawing near and enfolding one in his grace. In fact, the concluding words promise that he will bless his people.
   While these words are directed to the entire community, the pronouns are singular. The Lord blesses the whole by blessing individuals; he blesses individuals by blessing the whole. "The Lord bless you and keep you" are words of reminder, of attestation of promise. The buttressing words "and keep you" further explain his blessing. God's intention for his people is their good; he will preserve them to enjoy that good.
   The words "make his face shine upon you" recall the experience of Moses on Mount Sinai (see Exodus 34:29-35). As his glory had caused Moses' face to shine, so the Lord desires to make his presence known to all his people. When Moses was on the mountain, it was in the context of terror. But God had come down in grace; his revelation was of mercy. Hence we have the splendidly suitable tie of the light of his face and the grace of his presence.
   The Hebrew word shalom ("peace") is here seen in its most expressive fullness, not just as an absence of war, but as the positive state of rightness and the fullness of well-being. This kind of peace comes only from the Lord. The expression "turn his face" suggests pleasure and affection and is functionally equivalent to "smile."
   The Lord says that this prayer is the means of placing his name on his people. Since "the Lord" itself is a term of blessing whereby the eternal God states his relatedness to his people, these words of blessing could not be more appropriate. The prayer is designed to help the people experience the reality of the blessing of the Lord.