Nazir, Chapter 1, Mishnah 2. This mishnah deals with the various forms of nazirite vows and with the wordings by which a person accepts nezirus upon himself.
Accepting nezirus by mentioning one of the nazir's prohibitions:
The mishnah discusses a person who says one of the following expressions:
"Hareini nazir min hacharzanim" - charzanim are grape seeds.
"Umin hazagim" - the grape skins.
"Umin hatiglachas" - that he be a nazir with regard to cutting his hair.
"Umin hatumah" - that he be a nazir with regard to becoming tamei.
All of these are things that are forbidden to a nazir.
"Harei zeh nazir vechol dikdukei nezirus alav" - it is enough that he singled out one of the acts forbidden to a nazir and accepted it upon himself in order to be considered a nazir, and all the details of nezirus apply to him. In other words, even though he accepted upon himself only one particular category of the actions forbidden to a nazir, that is sufficient to make him a full nazir.
Nezir Shimshon:
Shimshon was a nazir all the days of his life, and one who says any of the following expressions is referring to him:
"Hareini k'Shimshon" - I wish to be like Shimshon, who was a nazir.
"K'ven Manoach" - Shimshon was the son of Manoach.
"K'ba'al Delilah" - this too was Shimshon.
"K'mi she'akar daltos Azah" - a deed that Shimshon performed.
"K'mi shenikru Pelishtim es einav" - as happened to Shimshon.
Some understand that he must first say "Shimshon ben Manoach" and then add one of these descriptions, while others say that it is enough even if he said only one of those descriptions on its own. "Harei zeh nezir Shimshon" - he becomes a nezir Shimshon, meaning that he has accepted upon himself a nazirite vow for all the days of his life.
Nezir olam:
A few words are missing from the mishnah at this point, since from here on it turns to a different category of nezirus: "Vechen ha'omer hareini nezir olam, harei hu nazir kol yamav" - one who says that he wishes to be a nezir olam, a nazir forever, is a nazir for his entire life.
"Im kein, mah bein nezir olam linzir Shimshon?" - If so, what is the difference between a nezir olam and a nezir Shimshon?
Nezir olam: "Hichbid se'aro - meikel bata'ar". When his hair becomes heavy for him - and it is understood that this happens once in twelve months - he may thin out his hair with a razor. He does not shave his hair off completely, but he trims it once in twelve months, and when he does so he brings three animals as offerings, the same animals that a person brings upon completing his nezirus. And if he became tamei, a nezir olam brings the offering that a nazir who became tamei brings: two birds and a lamb as an asham.
Nezir Shimshon: even if his hair becomes heavy for him, he does not cut his hair at all. And so too regarding tumah: while the laws of tumah apply to an ordinary nazir and to a nezir olam, a nezir Shimshon does not bring an offering for tumah.
And the Gemara adds: not only does he not bring an offering for tumah, but he is even permitted to become tamei. This is an exception in the case of a nezir Shimshon.