Shevuos Daf 23 חג השבועות דַף 23

Rava proved from the Mishnah that “eating” includes drinking. The Mishnah taught that one who swore not to eat, and then ate and drank, is only liable once. If “eating” does not include drinking, what is the novelty? Would the Mishnah need to teach he is not liable a second time if he ate and worked?! Abaye asked Rava that the opposite can be proven from the later case of the Mishnah, that if one swore “I will not eat and I will not drink,” and then ate and drank, he is liable twice. If swearing not to eat already prohibits drinking, then the second shevuah not to drink should be ineffective, since a shevuah to adhere to a mitzvah is invalid!? Rava first explained the Mishnah’s case that he swore, “I will not drink and I will not eat,” where the second shevuah adds to the first, but this is rejected. Ultimately, the Gemara answers that since he swore not to eat and additionally swore not to drink, גלי אדעתיה דהך אכילה דאמר אכילה גרידתא היא – he revealed his intent that the “eating” which he said referred to eating alone, and not drinking.

The Mishnah taught that one who swears not to eat, and ate multiple types of bread, is only liable once. However, one who specifically swore not to eat “wheat bread, barley bread, or spelt bread” is liable separately for each. The Gemara ultimately explains that his mentioning “bread” three times proves that he means to divide the shevuos. The Gemara asks, however, about the Mishnah’s later case, that one who swore not to drink “wine, oil, or honey” is liable for each violation. Here, perhaps he specified these beverages merely to permit himself in others!? Rav Pappa answered that the case is במונחין לפניו – where [these three liquids] are placed before him. After the Gemara rejects various expressions he could have used, it ultimately explains that he could have sworn "שלא אשתה אלו ומינייהו" – that I will not drink from these, nor their types. By specifying each beverage by name, he separated them into distinct shevuos. Rav Acha brei d’Rav Ika said the case is where his friend was pressuring him, saying, “Come drink wine, oil, and honey with me.” Since he could have sworn not to drink with him (which would prohibit these three drinks), and instead named the three beverages, he meant to separate the shevuos.

The Mishnah taught that one who swore not to eat, and ate forbidden foods (נבילות, טריפות, etc.), is liable. This is explained here to be במפרש – where he explicitly specified in his shevuah not to eat נבילות, etc. The Gemara objects that the shevuah should still be ineffective, since מושבע מהר סיני הוא – he is already sworn from Har Sinai not to eat forbidden foods!? Rav, Shmuel, and Rebbe Yochanan answer: בכולל דברים המותרין עם דברים האסורין – the case is with one who included in his shevuah permitted items along with forbidden items (i.e., he swore not to eat נבילות or kosher meat), and since the shevuah takes effect regarding the permitted items, it is also effective for the forbidden items, based on the principle of "איסור כולל". Reish Lakish explains the case is one whose shevuah prohibited even a כל שהוא of נבילה, which was previously only liable for a כזית. According to the Rabbonon on Daf 19b, this occurs במפרש חצי שיעור – with one who explicitly specifies to prohibit half the requisite amount, and according to Rebbe Akiva there, every standard shevuah prohibits a כל שהוא.