Shevuot 23B

ודלמא על ידי תערובת?

The Talmud rejects this: But if he had said it that way, perhaps his oath could be interpreted to prohibit only bread made from a mixture of all these grains.

אימא ״וכן של שעורים וכן של כוסמין״; ״פת״ ״פת״ למה לי? שמע מינה לחלק.

The Talmud suggests: If the specification in the Mishnah serves merely to ensure that his oath does not extend to other foods, have him say: Bread made from wheat and so from barley and so from spelt. Why do I need to repeat: Bread, bread, each time? Conclude from it that the point of repeating the word bread each time is to individuate each statement as a separate oath.

״שבועה שלא אשתה״ ושתה משקין הרבה, אינו חייב אלא אחת כו׳. בשלמא התם, דאמרת מייתרא ליה ״פת״ ״פת״ לחיובא; אלא הכא, מאי הוה למימר? דלמא למיפטר נפשיה ממשקין אחריני קאתי!

§ The Mishnah teaches: If he said: On my oath I will not drink, and then he drank several kinds of liquids, he is liable to bring only one offering. If he says: On my oath I will not drink wine, or oil, or honey, and he drank all of them, he is liable to bring an offering for each and every one. The Talmud asks: Granted, there, in the case of the bread, the ruling of the Mishnah is understood, as you said that the word bread before barley, and the word bread before spelt are superfluous and serve to extend his liability so that each is considered an independent oath. But here, where there is no superfluous language, what was there to say? Perhaps the oath comes to ensure that he exempts himself so that the oath does not extend to other liquids. Since that is a possibility, he should not be liable for breaking 3 separate oaths when he drank all 3 liquids.