(Mishnah): If one said 'Konam, I will not taste wine today', it is forbidden only until nightfall;

'This Shabbos (week)', it is forbidden the entire week, and [also] Shabbos of the previous [week, i.e. he vowed on Shabbos];

'This month is Asur' - he is forbidden the entire month, and the coming Rosh Chodesh;

'This year is Asur', it is forbidden the entire year, and the coming Rosh Hashanah;

'This Shavu'a (Shemitah cycle) is Asur', he is forbidden the entire Shavu'a, and [also] Shemitah of the previous [Shavu'a, i.e. he vowed in Shemitah. We explained this based on NICHMAD L'MAR'EH.]

Note: It seems that also regarding 'this month' and 'this year', he vowed on Rosh Chodesh and Rosh Hashanah. Then, obviously the day itself is forbidden; the Chidush is that also the coming Rosh Chodesh or Rosh Hashanah is forbidden.

If he said 'one day', 'one Shabbos', 'one month', 'one year', or 'one Shavu'a', he is forbidden [for that amount of time,] from day to day.

(Gemara) Inference: [He is forbidden only until dark] implies that after dark, he is permitted.

Question: Does this not argue with R. Yochanan? R. Yochanan said that vows follow Leshon Bnei Adam!

Is it not the way of a person [who did not eat from morning until now] to say to his friend at night 'I did not taste anything today'?!' (This shows that when people speak, 'today' includes the following night!)

[We can learn also from the day] after [night]. Is it not the way of a person [who did not eat last night] to say to his friend in the morning 'I did not taste anything [last] night.' Does he say 'today'?!

Does the [following] not argue [and show that in Leshon Bnei Adam, the night is part of the previous day?! One who says that that he will do something a certain day, he says] 'this day from this Shabbos' (e.g. Shelishi of Shabbos Bamidbar), or 'this Shabbos (week), from this day', or 'this day (e.g. the third day from today - he means from morning of the third day until morning of the fourth!)

Conclusion: [Is our Mishnah] like the opinion that Nedarim follow Leshon Bnei Adam?! Rather, here (our Mishnah) is like the opinion that Nedarim follow Leshon ha'Torah. (We explained this like MEICHAL HA'MAYIM.)

Resolution (R. Yonah Botzriyah): It is the way of a person to tell his friend 'wait for me today' (and he means until dark. I.e. in Leshon Bnei Adam, the day is until dark. Our Mishnah can hold that Nedarim follow Leshon Bnei Adam! - PNEI MOSHE)

(Mishnah): (If one said 'Konam wine, I will not taste it for a year', and the year was made a leap year, he is forbidden in it and its Ibur (Adar Sheni).) 'Until the beginning of Adar' is until Rosh [Chodesh] Adar Rishon. 'Until the end of Adar' is until the end of Adar Rishon.

Inference: [The Reisha] teaches that Nisan is Rosh Hashanah for Nedarim. (If it were Tishrei, obviously he is forbidden in Adar Sheni, for he is forbidden until Tishrei!)

Rebuttal: [We can say that] Tishrei is Rosh Hashanah for Nedarim. [The Chidush is], do not say that Adar Sheni is [an extra month] in place of Elul, and he is permitted in Elul. Therefore, it needs to say that he is forbidden in it and its Ibur.

If he said 'one day', 'one Shabbos', 'one month', 'one year', or 'one Shavu'a', he is forbidden for that amount of time, from day to day, from hour to hour (until the same hour of the day that he vowed).

A Beraisa [explicitly] teaches from hour to hour.

(R. Acha citing R. Avahu citing R. Yosi ben Chaninah): One may not fast until six hours on Shabbos.

Support (R. Yosi): Our Mishnah teaches so! If they were fasting [for rain], and rain fell for them before midday, they do not complete - until then is morning. [If it fell] After midday, they complete - the majority of the day already passed in Kedushah. (Regarding Shabbos, it is as if he fasted the entire day.)

R. Yochanan's words show that one may fast for hours (even if he already ate, or will eat later in the day, it is called a fast - TOSFOS Avodah Zarah 34a DH Mis'anin);

R. Yochanan used to say 'I am in my Ta'anis until I finish [learning] my Perek or my Parshah.' (Since he can finish the Perek or Parshah before night, this is Ta'anis Sha'os - CHASAM SOFER citing R. NASAN ADLER.)

R. Yonah's words show that one may fast for hours;

R. Yonah was in Tzur, and heard that R. Yosi's son died. Even though he had already eaten cheese and drank water, he finished the day in a fast.

Rav's words show that one may fast for hours;

(Rav): One may borrow a fast [if he cannot complete it, he eats] and he pays (completes the remaining hours on another day).

Shmuel: Did he vow [that he must fast for an entire day?! He merely accepted to afflict himself, and he did so!]

If one vowed to fast, and forgot, and ate a k'Zayis, he lost his Ta'anis.

(R. Ba citing Rabanan there (in Bavel)): This is if he said [that he will fast] a day Stam, but if he said 'this day', he fasts and completes [the rest of the day].

Limitation: This is only if he ate, but if he tasted [and spit it out], no.

(R. Ba Chasida citing R. Ze'ira): Tasting does not require a Brachah, it is not theft (if he who pretends that he wants to buy, so sellers let him taste. This was permitted only for one who let blood and cannot afford wine, but in any case it is not considered theft - TAL TORAH), we are not concerned for Demai (one may taste Safek Tevel), and it does not interrupt a fast.

If an individual decreed a fast on himself, he may eat and drink after dark (the night before). If he said [that he accepts] like a Ta'anis Tzibur, he may eat and drink during the day [before, but not after dark].

If he vowed to fast, and it turns out [some of the days were] Yom Tov or Shabbos, he is lashed [mid'Rabanan, for accepting to fast when it is forbidden] and he does not need a Heter from a Chacham;

If he vowed to fast, and it turns out [some were] days written in Megilas Ta'anis (a list of Yamim Tovim mid'Rabanan on which one may not fast) - R. Chizkiyah citing R. Yudan, and R. Yirmeyah citing R. Chiya bar Aba - one said that he fasts and does not complete [the fast]. One said that he is lashed and he does not need a Heter Chacham.

Limitation: This is before Megilas Ta'anis was Batel, but after Megilas Ta'anis was Batel, all these are Batel (he fasts all that he accepted).

(R. Chananyah and R. Yonason): Megilas Ta'anis is Batel.

(R. Yehoshua ben Levi): Megilas Ta'anis is Batel.

Objection (R. Yochanan): Last night, I sat and taught an episode that they decreed a fast during Chanukah in Lud, and R. Eliezer got up and cut his hair, and R. Yehoshua bathed. R. Yehoshua told [those who fasted] "go fast [after Chanukah, to atone] for fasting [during Chanukah]!

And you say that Megilas Ta'anis is Batel?! (If so, there was no reason not to fast! This is difficult only if the episode was after the Churban. Perhaps R. Yochanan had a tradition that it was so. Alternatively, before the Churban, R. Yochanan ben Zakai was alive, and R. Yehoshua would not rule [that they must fast again] in front of his Rebbi. - PF)

Answer (R. Aba): Even if you will say that [the rest of] Megilas Ta'anis is Batel, [the Isurim of] Chanukah and Purim are not Batel.

Support: The actions of Rabanan show that Megilas Ta'anis is Batel;

R. Yonason fasted every Erev Rosh Hashanah. (Megilas Ta'anis forbids to complete a fast on Erev Shabbos or Erev Yom Tov - SHA'AREI TORAS ERETZ YISRAEL, Ta'anis 2:12.) R. Avun fasted every Erev Shabbos (in order to eat Seudas Shabbos with appetite - Magihah in Maharam Di Lunzano). R. Ze'irah fasted 300 fasts, and some say 900 fasts, and he was not concerned for Megilas Ta'anis.

R. Yakov bar Acha instructed teachers of children "if a woman (who brings her son to you) will ask you, tell her that one may fast on any day, except for Shabbos, Yom Tov, Rosh Chodesh, Chol ha'Mo'ed, Chanukah and Purim."