Shevuos Daf 24 חג השבועות דַף 24

On the previous Daf, Rebbe Yochanan explained that a shevuah not to eat נבילות took effect because he included permitted items in his shevuah, using the principle of איסור כולל. Reish Lakish rejected Rebbe Yochanan’s interpretation, because he holds איסור כולל only applies באיסור הבא מאליו – with a prohibition which comes by itself (i.e., a standard איסור imposed by the Torah, e.g., Yom Kippur, which imposes a second prohibition on eating נבילה, along with all permitted foods). But באיסור הבא על ידי עצמו – with a prohibition which comes about through [the man] himself, such as a shevuah where the person creates the איסור, the principle of איסור כולל does not apply. In the Mishnah, Rebbe Shimon held that one who eats נבילה does not transgress his shevuah. According to Rebbe Yochanan, the reason is that Rebbe Shimon entirely rejects the principle of איסור כולל, as he said in a Baraisa that one who eats נבילה on Yom Kippur is פטור, in opposition to the Rabbonon. Although Yom Kippur prohibits eating all foods, Rebbe Shimon holds its prohibition still does not take effect on נבילה.

Tannaim argue about איסור כולל – a more inclusive prohibition (where the second איסור prohibits more items than the first, such as eating on Yom Kippur), if that second איסור takes effect on items already prohibited (such as נבילה). Rava explains the opinion who does hold that איסור כולל takes effect on the first prohibition: מידי דהוה אאיסור מוסיף – it is similar to a more expansive prohibition (where the second איסור adds to the prohibition already on this item, e.g., forbidden food becoming prohibited even in benefit). Just as with איסור מוסיף, the second איסור (the second eating prohibition) takes effect alongside its new aspect (the prohibited benefit), so too with איסור כולל, the second איסור impacts the already prohibited items alongside the formerly permitted items. The opinion who rejects איסור כולל (Rebbe Shimon) holds a second איסור only takes effect by איסור מוסיף, which is an expanded prohibition בחדא חתיכה – in a single item, as opposed to איסור כולל, which is בשתי חתיכות – in two items (i.e., the new prohibition forbids a different item).

Rava said that according to the opinion who holds of איסור כולל, if one swears not to eat figs, and then swears not to eat figs and grapes, מיגו דחייל אענבים חייל נמי אתאנים – since [the shevuah] takes effect regarding grapes, it also takes effect on figs, so eating figs would transgress both shevuos. The Gemara asks that this seems obvious and explains that one might have thought (as Reish Lakish above held) that the second איסור only takes effect with an איסור which comes by itself, but not with איסור הבא מעצמו – a prohibition which comes through [the man] himself, so Rava taught this is not so. This was challenged from a Mishnah which teaches that a single act of eating can obligate four חטאות and one אשם, where a tamei person ate חלב, which was both kodashim and נותר, on Yom Kippur (Rebbe Meir adds a fifth חטאת if he carried it in his mouth on Shabbos). According to Rava, the Mishnah should have listed a fifth חטאת, where he additionally swore not to eat dates or חלב, which takes effect on the חלב alongside the dates!? Six explanations are given why the Tanna did not teach this additional חטאת.