Avodah Zarah Daf 73 עבודה זרח דַף 73

Ra Dimi quoted Rebbe Yochanan saying that if one pours יין נסך from a barrel into a pit of wine, even for the entire day (so the יין נסך is eventually far more than a sixtieth of the total), ראשון ראשון בטל – every first drop of יין נסך is nullified as it falls in, so the wine remains permitted. The Gemara objects that the Mishnah states: יין נסך אסור ואוסר בכל שהוא – יין נסך is forbidden and prohibits a mixture with even a minimal amount. Presumably, the case is דקא נפיל איסורא לגו התירא – where the prohibited [wine] fell into the permitted [wine], and even a single drop prohibits the entire mixture!? The Gemara answers that the Mishnah’s case is the reverse, דקא נפיל התירא לגו איסורא – where permitted [wine] fell into prohibited [wine], where each successive permitted drop of wine becomes nullified and forbidden, so the mixture is forbidden even if the permitted amount eventually greatly exceeds the יין נסך. Rav Yitzchak bar Yosef limits the application of "ראשון ראשון בטל" to a small pitcher, whose liquid flow is small (and separate), but חבית דנפיש עמודיה – wine poured from a barrel, whose flow is large, the entire flow is considered as entering the mixture simultaneously, and the forbidden drops are not successively nullified.

Ravin quoted Rebbe Yochanan saying that if יין נסך fell into a pit of wine, ונפל שם קיתון של מים – and a flask of water also fell in, רואין את ההיתר כאילו אינו – we view the permitted [wine] as if it is not there, והשאר מים רבין עליו ומבטלין אותו – and as for the remaining [prohibited wine], the water overcomes it and nullifies it. He disagrees with the earlier versions of Rebbe Yochanan, and holds a minute amount of יין נסך always prohibits wine, regardless of which fell into which. Here, however, the יין נסך does not prohibit the wine, because instead, the water nullifies the יין נסך (if there is not enough יין נסך to flavor the water).

Rav Shmuel bar Yehudah reported that Rebbe Yochanan only applies this leniency if the water actually fell before the יין נסך. If the יין נסך fell in first, מצא מין את מינו וניעור – the type found its own type and was “awakened”, i.e., the permitted wine itself becomes forbidden, and cannot be permitted via the water. In another version, Rav Shmuel bar Yehudah says that even if the water fell afterwards, it would still nullify the יין נסך.

The Mishnah taught that יין נסך prohibits wine with a משהו, and water if it transmits flavor. It concludes: זה הכלל – this is the rule: מין במינו במשהו – a forbidden substance of one type prohibits a mixture of its own type with even a minimal amount; שלא במינו בנותן טעם – but only prohibits another type where it gives flavor to the mixture. Rav and Shmuel say this rule applies to כל איסורין שבתורה – all prohibitions in the Torah, and the Mishnah’s additional clause ("זה הכלל") means to include all איסורין. Rebbe Yochanan and Reish Lakish say that for most prohibitions, even מין במינו only prohibits where it is נותן טעם. מין במינו only prohibits with a משהו in the cases of יין נסך and טבל (and the "זה הכלל" of the Mishnah means to add טבל). These two exceptions are explained: יין נסך has this stringency, משום חומרא דעבודת כוכבים – because of the severity of idolatry. טבל has this stringency, because כהיתירו כך איסורו – like its becoming permitted, so is its prohibition. Shmuel taught that חטה אחת פוטרת את הכרי – a single wheat kernel (of terumah) exempts an entire pile from its terumah obligation. Just as a minimal amount releases grain from טבל, so too a minimal amount of טבל in a mixture prohibits it.