The Torah's attitude towards the nazir seems contradictory. On one hand, the Torah calls him "holy", as it says: "He is holy to Hashem" (Bamidbar 6:8). On the other hand, the nazir has to bring a sin-offering at the conclusion of the period of nezirut. Furthermore, it is written of a nazir who became defiled [with a dead body]: "He [the kohen] shall provide him atonement for having SINNED regarding the corpse" (6:11). Rashi explains: "Because he abstained from wine." Thus, is the nazir holy or a sinner?

The Tana'im dispute this in Masechet Ta'anit (11a): R. Elazar Hakapar son of Rebbe says: Against which person did [the nazir] sin? Rather, he suffered by abstaining from wine... if he, who abstained only from wine is called a SINNER, one who abstains from everything - all the more so! R. Elazar says, he is called HOLY, as it says, 'He shall be holy'. If he, who abstained from only one thing is called holy, one who abstains from everthing - all the more so!

We find the same contradiction in the Rambam. In Moreh Nevuchim (Guide to the Perplexed, 3:48) he writes: "One who is cautious of [wine] is called 'holy', and is placed on par with the Kohen Gadol in holiness." Yet, in Hilchot De'ot (3:1) he writes: "Perhaps a person will say: Since jealousy, desire, honor and the like are bad, and remove a person from the world, I will abstain from them completely to the extreme, so that he will not eat meat nor drink wine. This is also a bad path, and it is prohibited to follow. One who walks in this path is called a sinner."

If so, what is the proper way of serving Hashem - through abstention or by enjoying this world. The Netziv (Rav Naftali Zvi Yehuda Berlin, 19th century Lithuania), in his commentary to the Torah, writes as follows: It is worthwhile to abstain from physical pleasure in order to achieve the spiritual pleasure of clinging to Hashem. However, since this cause [of defilement] occurred to [the nazir] against his will, it is a sign that he is not worthy of such, and, if so, he suffered himself from wine for naught, and sought something above his level.

The Netziv explains that there is positive value to nezirut as a means of achieving great closeness to Hashem, but it is not appropriate for the average person.
Not everyone is on a high enough level to accept nezirut upon himself. If one stops his nezirut in the middle, this implies that he was not worthy from the beginning. Therefore, he is called a sinner, and has to bring atonement. This is why the Torah says, "for having sinned about the person" - i.e., that he sought to cling to Hashem on a level that is above him. The Netziv compares this to the 250 princes who offered the ketoret with Korach, who also wanted to achieve a closeness with G-d that was not appropriate for them. Therefore, it says there, "these sinners against their souls" (17:3).

Thus, as a general approach to serving Hashem, nezirut is not appropriate. The ideal for the average person is that he should sanctify the mundane; not live a life of abstention from the material world. However, there are some special individuals who are on a lofty level, for whom nezirut is holiness, as the prophet Amos writes: I established some of your sons as prophets and some of your young men as nazarites" (i.e. to become holy and achieve prophecy) (Amos 2:11).

However, sometimes even the average person needs to accept upon himself nezirut in order to protect himself from sin, as The Talmlud says: "one who sees a sotah (a woman suspected of adultery) in her degradation should abstain himself from wine" (Sotah 2a). This nezirut comes as necessary emergency medicine to protect one from sin. But, proper service of Hashem is to live a life of sanctity in the material world and to elevate and sanctify the secular.