Talmud - Nazir 33a נזיר ל״ג א׳

Abaye said: One must correct his understanding of the mishna, so that it deals with a situation where in addition to his first statement he said: Even if it is not so-and-so, I shall be a nazirite. And what is the meaning of the phrase: Whose statement was not fulfilled? It means: His first statement was not fulfilled, as it was not that person; rather, he is a nazirite because his last statement was fulfilled.

§ The mishna taught that if the individual walking toward them turned back, so that his identity remained unknown, not one of them is a nazirite. The Gemara clarifies: The reason is only because he turned back, from which it may be inferred that if that person comes before us and is identified, the one who said he would be a nazirite if it is so-and-so is considered to be a nazirite. The Gemara inquires: In accordance with whose opinion is this halakha?
This amud has no Gemara text, as in the classic Vilna layout it is entirely filled with the commentary of Tosafot.

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Nazir 33a examines Abaye's clarification of conditional nazirite vows and how an unresolved identity affects who becomes obligated as a nazirite.