By the NT period long hair was a ‘shame’ to a man (1 Cor. 11:14), although Paul made that statement to a church in Greece. Women, on the other hand, wore the hair long and practically uncut in both periods. The Talmud does mention women’s hairdressers, but the root of the word is ‘to plait’ [braid] rather than ‘to cut’. (New Bible Dictionary. Includes index. (electronic ed. of 2nd ed.). Wheaton, IL: Tyndale House.)according to the Jewish Mishna, not the Scriptures (Mishna, the first part of the Talmud, containing traditional oral interpretations of scriptural ordinances (halakhot, compiled by the rabbis about A.D. 200)), although double and triple vows for 60 and 100 days were sometimes made.
The Nazarite vow resembled the sanctified life of the priest, except that it was done spontaneously unto God by ordinary Israelites. This vow not only set a man apart but also shamed him, perhaps signifying the shame Jesus would endure. Some contend that since women took Nazarite vows (Numbers 6:2), they cut their hair as men did at the end of the vow. However, they have overlooked the fact that a woman’s vow was ALWAYS subject to her father’s or her husbands’ approval. Youth were also to confer with their parents. Obviously harmful, youthful zeal was to be avoided.
God Himself specifies this limitation in Numbers 30:1-16.
Since the entire point of his limitation was submission, and the Bible explicitly teaches that a woman’s hair is a symbol of submission, we should rightly believe that a women then let their hair be "unkempt" for the specified time, but they did not cut it at all. The vow at the maximum demands it simply be uncut. "As mentioned prior, there are at least three Biblical figures who did not cut their hair after taking the vow. In fact, the Talmud does mention women’s hairdressers, but the root of the word is "to plait" [braid] rather than "to cut". I said that it can be in a matter of personal sanctification."
The argument attempting to be made from those who reject the notion that a woman's hair should not be cut, in efforts to let the hair grow, is one from silence.
Some contend that while Paul taught men to have short hair, he himself took a Nazarite vow, basing this opinion on Acts 18:18:
"And Paul after this tarried there yet a good while, and then took his leave of the brethren and sailed thence into Syria and with him Priscilla and Aquila; having shorn his head in Cenchrea: for he had a vow."
There are other interpretations, however, the "vow" referred to in this verse is from "euche" the same word used in James 5:15 for the "prayer" of faith. It is possible that Paul did not shave his head because he was finishing a Nazarite vow. Even if he did the New Testament church did not maintain this practice. It is possible that he had just been delivered from the court of Gallio, so he needed to cut (“kiero”) his hair because he was going to prayer. It is possible that Paul knew that God cared what his hair looked like.
Greek scholars A.T. Robertson and Marvin Vincent agree that it was not a Nazarite vow for it could only be absolved only in Jerusalem. It is possible that the hair was only polled or trimmed, cut shorter, not “shaved” for there is a distinction as both verbs are contrasted in I Corinthians 11:6 it is not clear what sort of a vow Paul had taken or why he took it. It may have been a thank offering for the outcome at Corinth.
In Acts 21, I believe Paul is making a point to those who are truly Messianic Jews that to be a believer you do not have to abandon all your customs. Paul did take a vow, if Nazarite I believe like Calvin that it refers to a "superstitious" inclination of Paul. Even if Paul or Messianic Jews, for that matter, (the only ones who could remotely come close to relevantly exacting such a vow) take the Nazarite vow, in some sense, it does not disprove anything by point of fact.
In my opinion a Messianic Jew could possibly or probably (if so inclined) take a Nazarite vow. The vow however, as well as their entire living, will be moderated by the natural order and that order indeed further clarified by the New Testament. They would be aware of Paul's writings as it relates to hair for both genders. I believe that is possibly why God did command the youth to defer to parents. They, being cognizant of the desires of God, would not allow their youth's zeal to violate another principle. Especially in light of the later inspired text of the New Testament.
In addition it wasn't until the outpouring of the Holy Spirit that we became the Temples of that same Spirit. At least in this way. Some things were tolerated by God yet not approved. No matter what we concluded about any Nazarite vow Paul states clearly that a man is not to have long hair, and he expounded this under the inspiration of the Holy Spirit which more clearly states what God desires of men and women through their bodies, not just our cerebral forefronts. I beleive some principles of the Old Testament move into the New Testament by spiritual principle. Jesus carried over almost everyone of the Ten Commandments into the New Testament. No longer do men simply murder with swords and spears but also through their tongues.