Shevuos Daf 28 חג השבועות דַף 28

On the previous Daf, Rava said that if one swore not to eat a particular loaf, and he ate it, then if a כזית of it remains, he can request to annul the שבועה, but not if he ate the entire loaf. Two interpretations are given: (1) The case is one who swore "שלא אוכל" – that I will not eat this loaf. Although eating the first כזית already violates the שבועה, he can still annul the shevuah if a כזית remains, because מיגו דמהניא ליה שאלה אכזית בתרא – since the request (for a heter) is effective for him for the final כזית, מהניא ליה שאלה נמי אכזית קמא – the request is also effective (retroactively) for him for the first כזית (although it no longer exists). (2) The case is one who swore "שלא אוכלנה" – that I will not eat it. Although he does not violate the shevuah before eating the entire loaf, he cannot annul the shevuah if less than a כזית remains, because only a כזית is חשיב לאיתשולי עליה – significant enough to request (a heter) for it. Ameimar holds he can annul the shevuah even after eating the entire loaf. The shevuah’s impact is still relevant, since its consequence (either a korban or malkus) remains to be fulfilled, so it can be annulled.

Rava discusses one who swore שבועה שלא אוכל ככר זו אם אוכל זו – “An oath that I will not eat this loaf if I eat that loaf,” whereby one is the "איסור" (the potentially forbidden loaf) and the other is the "תנאי" (the conditional loaf whose eating triggers the shevuah). The shevuah comes into effect when he eats one of the loaves; therefore, if he forgot the shevuah at that time, the shevuah is void (because the requirement of "האדם בשבועה" is not fulfilled). Rava discusses four cases: (1) If he ate the "תנאי" having forgotten the shevuah, and the "איסור" while remembering it, he is exempt from malkus, since the shevuah did not take effect (the same applies if he ate the "איסור" בשוגג and then the "תנאי" במזיד). (2) If he ate the "תנאי" במזיד and then the "איסור" בשוגג, the shevuah took effect when he ate the תנאי, and he is liable for a korban for eating the איסור. (3) If he ate both בשוגג, he is exempt, since the shevuah was void. (4) If he ate both במזיד, then if he ate the תנאי first, he receives malkus for subsequently eating the איסור. If he ate the איסור first, he would receive malkus according to the opinion that התראת ספק – doubtful warning is valid (since it was unknown if he would later eat the תנאי).

Avimi asked his brother Aifa, if one swears twice (falsely) that he did not eat, what is the halachah? Aifa answered that he is only liable once, since a second shevuah cannot take effect after a first. Avimi replied: אישתבשת – you are mistaken: the first shevuah was immediately false, and no longer exists, and does not invalidate the second shevuah. Avimi then asked about one who first swore not to eat nine figs, then swore not to eat ten figs. Aifa said he is liable for both shevuos, because they are not identical, but again, Avimi said he was mistaken, because אי תשע לא אכיל עשר לא אכיל – if he cannot eat nine, he cannot possibly eat ten! Since violating the second shevuah necessitates violating the first, the second shevuah is redundant and is ineffective. Finally, Avimi asked about one who swore not to eat ten figs, and then swore not to eat nine. Aifa answered he is only liable once. Avimi again said he was mistaken, because the first shevuah still allows him to eat nine; thus, the second shevuah prohibits something new, and takes effect.