Commentary for Nazir 11:9

We learned [in a mishna]: If he shaved on day sixty less one, he has fulfilled his obligation - because the thirtieth day counts for both [terms of naziriteship].

Granted, according to Rav Mattana it works out well - who says that there is no such thing as a naziriteship less than thirty days, and [the nazir] does not shave until the thirty-first day -- we need this [additional] mishna because of the following: that the thirtieth day counts for him for both [terms of naziriteship]; that when he shaves for the first [term] on the thirtieth day, that day counts for him for both [terms], and from that very day the second term of naziriteship starts. Then, once fifty-nine days pass, the twenty-ninth [other texts read: fifty-ninth] day is considered for him to be the thirtieth day [of the second term] and part of a day is like an entire day.

However, according to Bar Padda - why do I need [this additional] mishna to teach us that the thirtieth day counts for him? Twenty-nine days is indeed a [complete] term of naziriteship.

Bar Padda could have said to you - I, who said that the fundamental term of naziriteship is just twenty-nine days, [also] rely on this -- that we learned this [additional] mishna and observed that it taught that if he shaved on the fifty-ninth day he has fulfilled his obligation, because the thirtieth day counts for him, because when he initially shaved on the thirtieth day it counted for him for both [terms], and not because we say that "part of a day is like a complete day", so that he would be considered as one who shaved on the thirty-first day. We see, then, that an unspecified naziriteship is only twenty-nine days, and therefore I said earlier that if he shaved on the thirtieth day he has fulfilled his obligation. But the reason of [the ruling of] this mishna is not, as you said, that "part of a day is like a complete day".

We learned: one who said "I am hereby a nazirite", if he became ritually impure on the thirtieth day, it negates the entire tally. Granted, according to Rav Mattena - who says that there is no term of naziriteship less than thirty days -- for this reason, when he becomes ritually impure on the thirtieth day, we consider it to be in the midst of "the fullness" [of days: Numbers 6:13] and it invalidates the entire [term]. And if you will ask: didn't Rav Mattena answer earlier that "part of the day is like an entire day"? Here too, let us say that part of the day is like an entire day, and if he becomes ritually impure on the thirtieth day, it should not invalidate anything. But that is no question: Rav Mattena would say to you that the first tanna of [the mishna wherein the statement] Rabbi Eliezer [appears] holds that we do not say "part of the day is like an entire day": the fact that we answer here [6b] that Rabbi Eliezer holds that part of the day is like an entire day implies that the first tanna of Rabbi Eliezer hold that we do not say "part of the day is like an entire day".

However, according to Bar Padda - who says that the fundamental term of naziriteship is only twenty-nine days -- why should it invalidate [the entire term]? He became ritually impure only after the "completion of the days of his naziriteship" [Numbers 6:13].