Terumos, chapter 8, mishnah 11. This mishnah closes the discussion of the obligation to guard Terumah from becoming tamei, and it is built on the mishnayos that came before it. The mishnah opens: "al zo v'al zo" - about this one and about that one.
Which cases do the words "al zo v'al zo" refer to:
Mishnah 8: Two barrels of wine, one of which became tamei and we do not know which, so that each of them is a case of doubtful tumah. Rabbi Yehoshua ruled that one may deliberately expose them so that they become definitely tamei, since there is no obligation to guard Terumah that is already of doubtful tumah from becoming further tamei.
Mishnah 9: Terumah wine flowing down into the lower pit, where it mixes with chullin and becomes tamei.
Mishnah 10: Terumah oil that spilled and was absorbed into the ground.
In all of those cases Rabbi Eliezer held that one may not take any action to directly render the wine or the oil tamei; rather, a person must sit with his hands folded and let events unfold on their own. Rabbi Yehoshua came and ruled leniently.
It is worth noting that although according to the Bartenura "al zo v'al zo" refers to mishnah 8 and mishnah 10 (and self-evidently to mishnah 9 as well), some have raised questions about applying this to mishnah 8, since there Rabbi Yehoshua did not permit directly rendering the doubtful barrel tamei, but only leaving it in its place, which is somewhat different from directly causing tumah. In any case, we will follow the Bartenura, and so the discussion concerns the last three cases.
Regarding this Rabbi Yehoshua said: "lo zo hi terumah she'ani muzhar aleha milletamei, ela mile'ochlah" - this is not the Terumah that the Torah spoke to me about when it warned me not to allow Terumah to become tamei. The obligation to guard Terumah from tumah certainly exists, but it was stated regarding cases in which the Terumah was fit to be eaten in any event; there I am required to guard it, so that it can be eaten by the kohanim. But in a situation where, even if I do not intervene, no kohen will eat this Terumah, I have no obligation whatsoever to guard it from becoming tamei.
It must be admitted that the mishnah's wording "ela mile'ochlah" requires explanation, and it may be possible to interpret it in other ways as well. The explanation we have suggested is: only Terumah that would have been fit to be eaten had I not acted - that is the Terumah I am required to guard.
"u'val tetamehu keitzad":
Where, then, does a person have an obligation to exert himself so that Terumah will not become tamei? On this the mishnah brings a fascinating case: "hayah over mimakom l'makom v'kikar shel terumah b'yado" - a person is traveling along the road with loaves of Terumah bread in his hand, and he is obligated to keep them in a state of taharah. And now he faces a dilemma.
"amar lo oved kochavim: ten achas mehen va'atamei, v'im lav harei ani metamei es kulah" - a non-Jew, who is considered tamei by rabbinic law, threatens him and makes a demand: either he is given one loaf which he will render tamei, or he will render all of the loaves tamei.
What should he do?
May he cause one loaf to become tamei in order to save the rest of the loaves, which is his obligation? Or perhaps he has no permission to cause one of them to become tamei, because that act is itself a transgression, and the end does not justify the means, and if they all become tamei - so be it?
Rabbi Eliezer is consistent with his approach throughout the chapter: "yitama kulah, ve'al yiten lo achas mehen viyitama" - let it all become tamei, rather than handing him one of them to defile. A person may not hand over even a single loaf in order to save the rest, because by giving it to the non-Jew who will defile it he is violating his duty to guard the loaves in taharah. Nor can one say that it is his fault that they all became tamei, since he could have saved the rest: it is not his fault at all. A person does what is incumbent upon him, and if a non-Jew wants to defile all the loaves against his will, that is not his doing and not his responsibility. He must guard the loaves as best he can, and considerations of usefulness, practicality or prioritizing are not taken into account. His duty is to do the right thing, and nothing more.
Rabbi Yehoshua is lenient, and in his view this is precisely the case where there is an obligation to act in order to protect the Terumah from becoming tamei: "yaniach lefanav achas mehen al hasela" - he should place one of them before him on the rock. He must choose one loaf and set it down before the non-Jew, and in that way, while one loaf becomes tamei, the rest of the loaves remain in their taharah. In his view this is the fulfillment of his obligation from the Torah, that is, he is obligated to act and save the loaves by sacrificing one of them.
And note the precise wording: he does not defile the loaf directly. He does not place the loaf into the non-Jew's hand, which would mean actively bringing tumah upon the Terumah bread - something he is not permitted to do. Rather, he chooses a loaf and sets it on the rock, and from here on, perhaps the non-Jew will change his mind and go on his way, and perhaps not; that is not his problem. He has designated one loaf as the loaf being sacrificed to save the rest, and if the non-Jew takes it and defiles it, not only has the man done nothing improper, but on the contrary, he has done everything required of him, since he protected the remaining loaves of Terumah from becoming tamei, and that is a requirement placed upon him according to Rabbi Yehoshua.
And the halachah follows Rabbi Yehoshua. It emerges, then, that in the earlier cases - where the Terumah is not fit to be eaten in any event, because it flowed into tumah, or was absorbed into the ground, or became of doubtful tumah status so that no one can eat it - it is permitted to act in order to salvage that Terumah. So, for example, with the oil that was absorbed into the ground: it is permitted to collect it in tamei vessels even though it thereby becomes tamei, since according to Rabbi Yehoshua this is not what the Torah prohibited. The Torah prohibited only oil that would have been eaten in any case, and here no one is going to eat this oil that was absorbed into the ground, and it is considered lost; therefore a person is permitted, and even obligated, to act to salvage it, and afterward he gives it to a kohen, and the kohen will use the tamei oil for lighting and burning, and that is perfectly fine.
In summary: the point of the Mishnah is that according to Rabbi Yehoshua one may directly defile the Terumah oil, because the alternative is worse. This is the pattern of the obligation: a person is commanded to protect Terumah from becoming tamei where it is going to be eaten; but where it will not be eaten in any event, it is permitted to defile it - and he is able to salvage the oil and give it to a kohen for his burning needs. Correspondingly, where the obligation does exist, as in the case of the traveler and the non-Jew, Rabbi Yehoshua requires him to act and place one loaf on the rock in order to save the rest. And with this the discussion of the obligation to guard Terumah from tumah concludes.