Question: "Why do some believe that Christ was a nazarite and wore long hair?" Answer: Jesus was not a nazarite.
Some have been misled by an erroneous interpretation of Matthew 2:23, "And he came and dwelt in a city called Nazareth: that it might be fulfilled which was spoken by the prophets, He shall be called a Nazarene."
Many have concluded that this prophecy had to be a written prophecy recorded somewhere in the Old Testament. This is an unfounded assumption.
Since they could not find anything in the Old Testament about Nazarenes, they guessed that some similar word must have been intended. Using this erroneous reasoning, they went one step further in their folly and assumed that this scripture was referring to the laws (NOT prophecy) about nazarites.
Notice that the prophecy said that Christ would be called a Nazarene, not a nazarite. A Nazarene is one who lives in Nazareth; and a nazarite is one who has a nazarite vow, which is described in Numbers 6. Many Bible students have been confused by the similarity of these two words, although they are not at all related in their meanings. They are just as unrelated in meaning as some of our English words of today that have similar sounds, such as "encumber" and "cucumber." Christ was a Nazarene, a man from Nazareth. He was not a long-haired nazarite. A nazarite was forbidden to drink wine, but Christ drank wine on numerous occasions. Either He was never a nazarite — or He broke His vows!
The prophecy — that the Saviour would be called a Nazarene — was not "written" in the Scriptures. Matthew says it was "spoken by the prophets." It was a universally recognized oral prophecy that was authoritatively preserved from generation to generation by the priests. It became a written prophecy only in New Testament times.