Commentary for Nedarim 2:1
וְאֵלּוּ מֻתָּרִין. חֻלִּין שֶׁאֹכַל לָךְ, כִּבְשַׂר חֲזִיר, כַּעֲבוֹדָה זָרָה, כְּעוֹרוֹת לְבוּבִין, כִּנְבֵלוֹת, כִּטְרֵפוֹת, כִּשְׁקָצִים, כִּרְמָשִׂים, כְּחַלַּת אַהֲרֹן וְכִתְרוּמָתוֹ, מֻתָּר. הָאוֹמֵר לְאִשְׁתּוֹ, הֲרֵי אַתְּ עָלַי כְּאִמָּא, פּוֹתְחִין לוֹ פֶתַח מִמָּקוֹם אַחֵר, שֶׁלֹּא יָקֵל רֹאשׁוֹ לְכָךְ. קוֹנָם שֶׁאֵינִי יָשֵׁן, שֶׁאֵינִי מְדַבֵּר, שֶׁאֵינִי מְהַלֵּךְ, הָאוֹמֵר לְאִשְׁתּוֹ, קוֹנָם שֶׁאֵינִי מְשַׁמְּשֵׁךְ, הֲרֵי זֶה בְלֹא יַחֵל דְּבָרוֹ. שְׁבוּעָה שֶׁאֵינִי יָשֵׁן, שֶׁאֵינִי מְדַבֵּר, שֶׁאֵינִי מְהַלֵּךְ, אָסוּר:
And these are permitted: (Let it be as) "chullin (non-consecrated food), what I eat from you." [(This is simply a sign, viz.: Just as "Chullin, what I eat from you" does not require consultation of a sage (for absolution), so all of these mentioned in the first part of our Mishnah do not require consultation of a sage.)], "As the flesh of pig," "As idolatry," "As the hides of levuvin" [They would incise the beast around the heart while it was still alive, take out the heart, and offer it to idolatry, and it is not permitted to derive benefit from idolatrous offerings.], "As neveiloth" (carcass), "As treifoth" (organically defective animals), "As shekatzim and remasim" (forbidden animals and reptiles), "As the challah of Aaron" [the first of the Cohanim] and as his terumah [Challah is not "a thing that is vowed," challah and terumah not coming through vow and gift.] — these are permitted [For Scripture states (Numbers 30:3): "A man, if he vow a vow" — (The forsworn object does not become forbidden to him) unless he vows (to abjure it) against something which is itself vowed (and not forbidden by its very nature). As to (1:4): "A sin-offering, that I not eat from you," which is forbidden, even though it (a sin-offering) is not a thing that is vowed, there (the reason is that) it is possible to make oneself liable for a sin-offering as the result of a vow, as when one takes a Nazirite vow and becomes liable for a sin-offering.] If one says to his wife: "You are (forbidden) to me as my mother" [Even though this is not "something that is vowed," it is more stringent than all of those mentioned above, requiring absolution by the rabbis if he is an am ha'aretz (unlearned)], an opening is provided for him from "elsewhere" [i.e., an opening and a "rationale" is provided for his recantation, it not sufficing that he be asked "Do you regret it now?" or "Do you still feel the same?" (all this,) so that he not treat the matter lightly (and not become accustomed to forbidding his wife to himself.)] "Konam" that I not sleep, that I not speak, that I not walk, [he may not break his word. This, by rabbinical ordinance; for, by Torah law such a vow does not "take," vows taking only with matters of "substance"]; if one says to his wife: "Konem that I not cohabit with you," he comes under (Numbers 30:3): "He may not break his word." [The gemara asks: Is he not obliged to (cohabit with) her? How can he release himself from this obligation through his vow? This is comparable to one's forbidding his friend's fruit to his friend! And the gemara answers: (It obtains) when he says: "The pleasure of cohabiting with you is konam to me," where he forbids the pleasure to himself; and a man may not be fed what is forbidden to him.] (If he says;) "An oath" that I not sleep, that I not speak, that I not walk — it is forbidden. [It is forbidden by Torah law; for oaths "take" both with things of substance and with things lacking substance. And if he swears that he will not sleep three days in a row, day and night, he receives stripes and sleeps immediately, having sworn to do the impossible.]
Bartenura on Mishnah Nedarim
English Explanation of Mishnah Nedarim
If one says to his wife, “Behold! You are like my mother to me”, he must be given an opening on other grounds, in order that he should not act lightly in such matters.
[If one says,] “Konam if I sleep”; “If I speak”; or “If I walk”; or if one says to his wife, “Konam if I cohabit with you,” he is liable to [the biblical prohibition] “he shall not break his word” (Numbers 30:.
[If he says,] “I swear] an oath not to sleep”, or, “talk,” or, “walk,” he is forbidden [to do so].
The first section of this mishnah deals with vows that are not binding. The second and third sections deal with vow that are semi-binding.
Section one: I shall explain each of these cases one at time.
“What I might eat of yours shall be unconsecrated”: Unconsecrated food is permitted, hence he has not stated that anything should be prohibited to him.
“As the flesh of the swine”: Vow formulas only work if the object used as a vow is something which can be vowed/dedicated to the Temple, such as an offering. While swine and the subsequent objects listed in this mishnah are forbidden, they cannot be offered to the Temple, and hence the vow is invalid.
“As an object of idolatrous worship”: This vow does not work for the same reason as above.
“As hides pierced at the heart”: These were used in idol worship.
“As carrion”; “As terefoth”; “As abominations”; “As creeping things”: These are all things which Jews may not eat. Carrion is an animal which was slaughtered improperly, “terefoth” are animals which died or would have died without being slaughtered. “Abominations and creeping things” are forbidden reptiles and other small animals, all of which are forbidden to eat. Again, the vow formula is ineffective because he didn’t vow using something which can be donated to the Temple.
“As Aaron’s dough”; “As his terumah”: These are both gifts that must be given to priests (Aaron’s sons). They are forbidden for consumption for non-priestly Jews. However, since one cannot offer them to the Temple, they cannot be used in vow formulas.
Section two: In this case, a husband attempts to forbid his wife to himself sexually, by stating that she should be to him like his mother, who is obviously prohibited to him (nothing Oedipal here). The vow does not work, since he didn’t use something that can be vowed as part of his vow formula. However, the rabbis did not want people to take these matters lightly and hence they said that he had to find an “opening” for breaking his vow. For this, he will need to see a Sage. We will learn more about how this is done towards the end of the tractate.
Section three: At the end of the previous chapter we learned that a vow does not work on something that has no substance. Therefore, when one says “Konam (a valid formula) that I should not do something” the vow is not valid, since actions do not have substance. However, our mishnah rules that the one who took such a vow should nevertheless keep his word. He still must follow the prohibition in Numbers 30:3, that a person must do all that he promised.
In contrast, oaths (shevuoth) can be made on actions, for an oath relates to the person and not to the object. Therefore, one who swears an oath not to do something is bound by Torah law to keep his word.