MISHNA: If one takes an oath to refrain from performing a mitzva and he does not refrain, he is exempt from bringing an offering for an oath on an utterance. If he takes an oath to perform a mitzva and he does not perform it, he is also exempt, though it would have been fitting to claim that he is liable to bring the offering, in accordance with the statement of Rabbi Yehuda ben Beteira.

The mishna explains: Rabbi Yehuda ben Beteira said: What? If, with regard to an oath concerning an optional matter, for which one is not under oath from Mount Sinai, he is liable for breaking it, then with regard to an oath about a mitzva, for which he is under oath from Mount Sinai, is it not logical that he would be liable for breaking it?

The Rabbis said to him: No, if you said that one is liable for breaking an oath concerning an optional action, where the Torah rendered one liable for a negative oath not to perform it like for a positive oath to perform it, shall you also say one is liable with regard to breaking an oath concerning a mitzva, where the Torah did not render one liable for a negative oath like for a positive oath, since if one takes an oath to refrain from performing a mitzva and did not refrain, he is exempt.

GEMARA: The Sages taught in a baraita: One might have thought that when one takes an oath to refrain from performing a mitzva and he does not refrain, he would be liable to bring an offering for an oath on an utterance. To counter this, the verse states: “To do evil, or to do good” (Leviticus 5:4). Just as doing good is referring to an oath about an optional action, so too, doing evil is referring to an oath about an optional action. I will therefore exclude from liability one who takes an oath to refrain from performing a mitzva and does not refrain, so that he is exempt from bringing the offering.

The baraita continues: One might have thought that when one takes an oath to perform a mitzva and does not perform it, that he would be liable. To counter this, the verse states: “To do evil, or to do good.” Just as doing evil is referring to an oath about an optional action, so too, doing good is referring to an oath about an optional action. I will therefore exclude from liability one who takes an oath to perform a mitzva and does not perform it, so that he is exempt from bringing the offering.

One might have thought that when one takes an oath to harm himself and he does not harm himself, that he could be exempt from liability. The verse states: “To do evil, or to do good.” Just as doing good is referring to an oath about an optional action, so too, doing evil is referring to an oath about an optional action. I include as liable one who takes an oath to harm himself and does not harm himself, since it is his prerogative to harm himself or not.

One might have thought that when one takes an oath to harm others and does not harm them, that he would be liable. To counter this, the verse states: “To do evil, or to do good.” Just as doing good is referring to an oath about an optional action, so too, doing evil is referring to an oath about an optional action. I will therefore exclude from liability one who takes an oath to harm others and he does not harm them, since it is not his prerogative to do so. From where is it derived that taking an oath that concerns doing good to others is included among the oaths for which one may be liable? The verse states: “Or to do good.” And what is harming others? An example is when one takes an oath saying: I will strike so-and-so and injure his brain.

The baraita assumes throughout that “to do evil, or to do good” is referring to optional actions. The Gemara asks: But from where do we know that these verses are written referring to optional matters? Perhaps they are written referring to matters involving a mitzva.

The Gemara rejects this: This should not enter your mind, since we require that doing good be similar to doing evil, and doing evil be similar to doing good, as doing evil is juxtaposed to doing good in the verse. If one stipulates that the verse is referring to matters involving a mitzva, then just as doing good does not involve refraining from performing a mitzva, but must involve performing a mitzva, e.g., an oath to eat matza on Passover, so too, doing evil does not involve refraining from performing a mitzva, e.g., an oath not to eat leavened bread on Passover. The result of this reasoning is that doing evil in the verse is itself doing good, in that it will always involve taking oaths to keep mitzvot.

And likewise, doing good is juxtaposed to doing evil; just as doing evil does not involve performing a mitzva, as it would then not be doing evil, so too, doing good does not involve performing a mitzva. Doing good in the verse is itself doing evil, in that it does not involve the fulfillment of mitzvot.

The Gemara asks: If that is so, that doing evil and doing good are compared in this manner, you do not find that the verse can be interpreted even with regard to optional matters, as the same sort of contradiction could be generated.

Rather, one may derive that the verse is referring to optional matters from the fact that it was necessary for the verse to write “or to do good,” in order to include liability for oaths that involve doing good to others. Conclude from it that these verses are written referring to optional matters. As, if it should enter your mind that the verses are written referring to matters involving a mitzva, there is a difficulty: Now that doing evil to others has been included, i.e., when one takes an oath to refrain from performing a mitzva, is it necessary to mention doing good to others?

The Gemara challenges: But this “or” is necessary in order to separate them, i.e., to indicate that one can be liable for either type of oath. Had the verse said: To do evil and to do good, one might assume that one is liable only for oaths that involve both. The Gemara answers: A verse is unnecessary in order to separate, as it is clear that either sort of oath is included.

The Gemara asks: This works out well according to Rabbi Yonatan’s opinion concerning the interpretation of conjunctions, but according to Rabbi Yoshiya’s opinion, what can be said?

The Gemara explains: As it is taught in a baraita: From the verse: “A man who curses his father and his mother shall die” (Leviticus 20:9), I have derived only that one is liable if he curses both his father and his mother. From where do I derive that if one curses his father but not his mother, or his mother but not his father, he is liable? The continuation of the verse states: “His father and his mother he has cursed; his blood is upon him.” In the first part of the verse, the word “curses” is in proximity to “his father,” and in the last part of the verse, “cursed” is in proximity to “his mother.” This teaches that the verse is referring to both a case where he cursed only his father and a case where he cursed only his mother; this is the statement of Rabbi Yoshiya. Rabbi Yoshiya maintains that conjunctions are interpreted strictly unless the verse indicates otherwise.

Rabbi Yonatan says: There is no need for this derivation, because the phrase “his father and his mother” indicates that one is liable if he curses both of them together, and it also indicates that he is liable if he curses either one of them on their own,