Nedarim, Chapter 9, Mishnah 2. In the previous Mishnah we learned the concept of releasing a vow by means of a "pesach," an opening: some fact that, had the person known of it at the time he made his vow, he would never have vowed at all. On the basis of such an opening, a single sage (a Torah scholar) or a beis din can annul the vow. Our Mishnah introduces a further concept called "nolad" - an opening that did not exist at all at the time of the vow, but came into being only afterward. The question under discussion is whether an opening of this kind may be used.
The dispute between Rabbi Eliezer and the Sages:
"V'od amar Rabbi Eliezer: pos'chin b'nolad" - Rabbi Eliezer, who already discussed in the previous Mishnah whether the honor due to one's parents may serve as an opening, adds a further ruling here: an opening may be used even when it concerns something that was "born," that is, something that came into being only after the vow was made.
"Va'chachamim omrim" - the Sages disagree and hold that an opening that came into being afterward may not be used. The entire basis of an opening is the claim, "Had I known this at that time, I would never have vowed"; and when the matter did not exist at all at the time of the vow, the person cannot say that knowledge of this fact would have kept him from vowing, since the fact simply did not exist.
"Keitzad?" - the Mishnah's examples:
"Amar: konam she'eini neheneh l'ish ploni, v'na'aseh sofer" - a person vowed that he would derive no benefit from a certain man, and afterward that man became a sofer, that is, a scribe whose services the one who vowed now needs, or a Torah scholar whom he likewise needs. Now that the man has acquired this new standing, the one who vowed asks that the vow no longer remain in force - but at the time the vow was made, the man was not yet a scribe.
"O shehayah masi es b'no l'chupah karov" - the person vowed not to derive benefit from that man for a certain period of time, and within that period the man is about to marry off his son, and the one who vowed wishes to take part in the celebration. These circumstances too did not exist at the time of the vow.
"Konam l'bayis zeh she'eini nichnas, v'na'aseh beis haknesses" - a person vowed not to enter a certain house, and afterward that house became a synagogue.
In all of these cases the one who vowed comes before the sage or the beis din and claims: "Ilu hayisi yodea shehu na'aseh sofer, o shehu masi es b'no l'chupah karov, lo hayisi noder" - "Had I known that he would become a scribe, or that he would be marrying off his son shortly, I would never have vowed," and likewise "Ilu hayisi yodea shehu na'aseh beis haknesses, lo hayisi noder" - "Had I known that it would become a synagogue, I would never have vowed." This is the illustration of what is considered a nolad: in Rabbi Eliezer's view such an opening may be used to annul the vow, while in the view of the Sages an opening of this sort is not used.
A nolad that is common and frequent:
A point raised by the Gemara: although the Sages disagree with Rabbi Eliezer and hold that a nolad may not be used as an opening to annul a vow, this depends on how common that particular nolad is. When it is something ordinary and frequent, occurring regularly, even the Sages agree that a nolad of this kind can serve as an opening.
In summary: in this Mishnah we learned the law of the "nolad" - an opening that came into being only after the vow was made. Rabbi Eliezer holds "pos'chin b'nolad," while the Sages disagree, because a person cannot claim that he would have refrained from vowing on account of a fact that did not exist at the time. The Mishnah brought three examples: one who vowed not to derive benefit from a certain man and that man became a scribe; one who made such a vow and the man is about to marry off his son; and one who vowed not to enter a certain house and the house became a synagogue. We also learned from the Gemara that with a nolad that is common and frequent, even the Sages agree that it may be used as an opening.