The Nazarite vow could be for either “a man or woman” (v.1). It included a number of things:
1. No wine (v.3)
2. No grapes or raisins (v.3).
3. No cutting your hair (v.5). This was a symbol for their dedication (v.7).
4. No going near a dead body (v.6).
This was a voluntary vow that the people could give to God. It is similar to deciding to abstain from marriage as a believer (Mt. 19:12). Some believers have the gift of celibacy (1 Cor. 7:7). While there is nothing wrong in getting married (1 Tim. 4:3-4), it is a voluntary decision to abstain from marriage. OT believers could voluntarily take on this Nazarite vow.
While the vow had negative consequences (being separate from these things), it also had positive consequences (being separate to Yahweh). In verses 2 and 8, we read that the person will “dedicate himself to the LORD.”
When the Nazarite brings his offering to God, he is supposed to shave off his hair and add that to the offering (v.18). Hair grows slowly. When you eventually cut off your hair, it would be a significant display to God of a long term sacrifice. In other words, you would be looking at the amount of time that it took for you to grow your hair, remembering the long sacrifice that you made for God. By burning your hair, it would be a physical way of saying that you are dedicating your life over to God.
It is unclear why these particular acts were forbidden for the Nazarite (e.g. wine, grapes, touching the dead, etc.). But these must have been a physical representation of some spiritual significance. Additionally, this vow has nothing to do with Jesus being from Nazareth, as some commentators hold. Ronald Allen writes, “The word Nazirite is sometimes confused with Nazarene, the word used to describe Jesus in terms of his hometown origin (see Matt 2:23; Mark 14:67; 16:6; Acts 24:5). While these words are based on the same root (nāzar, ‘to vow’), they are distinctive words.”
 Allen, R. B. Numbers. In F. E. Gaebelein (Ed.), The Expositor’s Bible Commentary, Volume 2: Genesis, Exodus, Leviticus, Numbers (F. E. Gaebelein, Ed.). Grand Rapids, MI: Zondervan Publishing House. 1990. 749.