- A neder of היום, שבת זו, etc.
The eighth Perek begins: קונם יין שאני טועם היום אינו אסור אלא עד שתחשך – If one says: “Wine is konam for my tasting today,” he is only forbidden until it gets dark. The term “today” does not imply a full twenty-four-hour period, but the remainder of that particular day. Similarly, if one makes a neder for “this week,” “this month,” this year,” or “this seven-year cycle,” he is forbidden until the end of each respective period. However, the Mishnah distinguishes between Shabbos and the Shemittah-year, both of which are considered the end of their respective time periods and are included in the neder, versus Rosh Chodesh and Rosh Hashanah, both of which are considered the beginning of the next time period and not include in the neder. If someone made a neder for “one day,” he is forbidden for one full twenty-four period from the time he made the neder. The same applies to a neder of one week, month, year, or seven-year cycle.
- לכשתחשך צריך שאילה לחכם
Rebbe Yirmiyah said: לכשתחשך צריך שאלה לחכם – When it gets dark, he must still ask a chochom for a heter for his neder, although the term of the neder ended already. Rav Yosef explained the reason: גזירה היום משום יום אחד – A Rabbinical decree of the neder of “today” was made because of possible confusion with the neder of “one day.” The Rabbis were concerned that if someone drinks wine after nightfall by a neder of “today” (which is permitted), people may assume the same applies to a neder of “one day,” and not wait the full twenty-four-hour period. To avoid this mistake, they required a person to seek a heter on his neder of “today” before partaking of the formerly prohibited substance. The Gemara clarifies that the reverse was unnecessary, namely, to require one who made a “one day” neder to seek a heter before drinking wine after twenty-four hours but before nightfall, because no one will think that a neder of “today” could possibly end before nightfall of that day. Ravina quoted the above ruling as being based on the statement of Rebbe Nassan, who said: כל הנודר כאילו בנה במה – Anyone who makes a neder, is as if he built an altar when it is forbidden, והמקיימו כאילו מקטיר עליה – and if he keeps the neder instead of seeking a heter, it is as if he sacrifices on it, which is liable to kares. The Ran explains that although the concern mentioned above is itself too remote to warrant requiring him to ask for a heter, since making the neder was additionally improper, the Rabbis required him to seek a heter.
- A neder of “a day”
The Gemara presents an inquiry: אמר קונם יין שאני טועם יום מאי - If he said: “Wine is konam for my tasting for a day,” what is the halacha? Is it like a neder of “today,” and forbidden only for the remainder of that day, or is it like “one day,” and forbidden for a full twenty-four hours? The Gemara attempts to resolve the question from our Mishnah, which taught that a neder of “today” is until the end of the day, which would imply that a neder of “a day” would not have the same halachah; rather, it would be for a full twenty-four hours. The Gemara responds that the reverse inference can be made from the second case of the Mishnah, which taught that a neder of “one day” is for a full day, which implies that a neder of “a day” would only be forbidden until the end of that day. Rather, no inference can be made from this Mishnah. Rav Ashi suggests another proof, but it is ultimately rejected, and the inquiry is left unresolved.
