Shevuot 27B

עד שיפרוט לך הכתוב ״יחדיו״.

unless the verse specifies that one is liable only if he curses both together. An example of a verse where the Torah specifies that the halakha applies only to the two elements in conjunction is: “You should not plow with an ox and a donkey together” (Deuteronomy 22:10).

אפילו תימא רבי יאשיה; וסבר לה כרבי עקיבא דדריש רבויי ומיעוטי, ואייתר ליה ״או״ לחלק.

The Talmud continues: You may even say that the verse is referring to optional matters according to the opinion of R' Yoshiya. He holds in accordance with the opinion of R' Akiva, who interprets the Torah using the hermeneutical principle of amplifications and restrictions (see 26a), and the word “or” is superfluous and is used to separate “to do evil” from “to do good.”

אי אמרת בשלמא בדבר הרשות כתיב, ממעט דבר מצוה; אלא אי אמרת בדבר מצוה כתיב, ממאי קא ממעט?

The Talmud explains how one derives that the oaths referred to in the verse are oaths about optional matters in accordance with R' Yoshiya, who interprets the verse in accordance with the principle of amplifications and restrictions: Granted, if you say that the verse about an oath on an utterance is written with regard to optional matters, the words “to do evil, or to do good” serve to restrict the meaning of the verse and exclude the application of an oath on an utterance to a matter involving a mitzva. The Talmud asks rhetorically: But if you say that the verse is written referring to a matter involving a mitzva, what do the words “to do evil, or to do good” serve to restrict?

אמר רבי יהודה בן בתירא: מה אם הרשות כו׳. ורבנן ⁠– שפיר קאמרי ליה לרבי יהודה בן בתירא!

§ The Mishnah teaches: R' 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 then asked him why he thinks one should be liable for an oath about a mitzva, since one would be exempt if it were inverted from positive to negative, rendering it an oath to refrain from performing a mitzva, which does not take effect. The Talmud comments: The Rabbis’ objection to the opinion of R' Yehuda ben Beteira is well stated.