And Rabbi Eliezer rejects this refutation because, in his opinion, permitting a rabbinic decree for the sake of a mitzva is preferable. We cannot derive through an a fortiori inference that since rabbinic decrees were not permitted for optional activities associated with rejoicing on festivals, they must not be permitted for the purpose of a mitzva on Shabbat. This is because it is possible that they permitted rabbinic decrees for mitzva purposes due to the importance of the mitzva.

It was taught in a baraita: Rabbi Eliezer said: What reason do I have? If actions that facilitate the performance of the mitzva and are done after the slaughter, such as cleaning the intestines which is permitted according all opinions, override Shabbat even though the mitzva has already been done, is it possible to say that actions that facilitate the performance of the mitzva and must be done before the slaughter do not also override Shabbat?

Rabbi Akiva said to him: What reason do I have to reject this comparison? If actions that facilitate the performance of the mitzva that are done after the slaughter override Shabbat, that is because slaughter has already overridden Shabbat and therefore an action that violates a rabbinic decree is performed, after Shabbat has already been overridden; can you say that actions that facilitate the performance of the mitzva and are done before the slaughter should override Shabbat even though slaughter has not yet overridden Shabbat? Alternatively, Rabbi Akiva has another reason: Perhaps the offering will be found to be disqualified due to a blemish and the person will be found to have violated Shabbat retroactively when he slaughtered the animal without fulfilling a mitzva.

Rabbi Eliezer rejects this argument: If so, if you are concerned about this possibility, it should also not be slaughtered; for perhaps the offering will be found to be invalid and the person will be found to have violated Shabbat retroactively. Rather, the course of the discussion must have gone as follows: Rabbi Akiva said this last reason to Rabbi Eliezer at the beginning and he refuted it as explained above; and then Rabbi Akiva said to him this other reason of: What reason do I have to reject this comparison? If actions that facilitate the performance of the mitzva override, etc.

We learned in the mishna that Rabbi Akiva responded and said to Rabbi Eliezer that the law governing the sprinkling of the purifying water of a red heifer proves that actions prohibited by a rabbinic decree, even when they are performed for the sake of a mitzva, do not override Shabbat. He then goes on to argue that we can reverse the order of the argument and conclude by way of an a fortiori inference that even slaughter does not override Shabbat. It was taught in a baraita that Rabbi Eliezer said to him about this: Akiva, you have lightheartedly responded to me with a faulty a fortiori inference with regard to slaughter. His death will be with slaughter; meaning, as punishment for this disrespect you will be slaughtered by other people. Rabbi Akiva said to him: My teacher, do not deny my contention at the time we are discussing this inference, for this is the tradition I received from you: Sprinkling is forbidden by rabbinic decree and does not override Shabbat.

The Gemara asks: Seeing that Rabbi Eliezer taught Rabbi Akiva this halakha that sprinkling purifying water does not override Shabbat, what is the reason he retracted his opinion? Ulla said: When Rabbi Eliezer taught him this halakha, he taught it to him with respect to sprinkling that is performed in order to enable a ritually impure priest to partake of teruma. This sprinkling does not override Shabbat because even separating teruma itself does not override Shabbat. But he never taught Rabbi Akiva this halakha with respect to sprinkling that is performed in order enable someone to eat of the Paschal lamb.

The Gemara notes that Rabbi Akiva as well, when he challenged Rabbi Eliezer, challenged him with regard to the halakha of sprinkling for teruma, and his objection should be understood as follows: Eating teruma is a mitzva, and sprinkling purifying water on someone who is ritually impure is only prohibited due to a rabbinic decree; nevertheless, sprinkling purifying water on a ritually impure priest, in order to enable him to eat teruma, is prohibited on Shabbat. Thus it follows by a fortiori inference that slaughter, which is a biblically prohibited labor, should certainly be forbidden on Shabbat, even when performed for the sake of a mitzva. And Rabbi Eliezer thought Rabbi Akiva was challenging him with regard to the halakha of sprinkling that is performed in order to enable someone to eat of the Paschal lamb; that is why he said that he disagreed about sprinkling as well.

Rabba raised an objection to Ulla’s explanation, based on a different baraita which states: Rabbi Akiva responded and said: The sprinkling of purifying water on someone who is ritually impure due to contact with a corpse proves the matter when his seventh day of impurity occurs on Shabbat and it is also the eve of Passover, for it is done for the sake of a mitzva, in order to allow the person to eat of the Paschal lamb, and it is prohibited only due to a rabbinic decree, and nonetheless it does not override Shabbat. From this baraita it is clear that Rabbi Akiva challenged Rabbi Eliezer with regard to the halakha of sprinkling that is performed in order to enable someone to eat the Paschal lamb.

Rather, we must reject Ulla’s explanation and say instead that Rabbi Eliezer certainly taught Rabbi Akiva about sprinkling that is performed in order to enable someone to eat of the Paschal lamb. And with regard to the question that seeing that Rabbi Eliezer himself taught him this halakha, what is the reason that Rabbi Eliezer refutes it, the Gemara answers: Rabbi Eliezer forgot his own teaching and Rabbi Akiva came to remind him of his teaching by drawing an a fortiori inference that would cause Rabbi Eliezer to remember what he himself had taught. The Gemara asks: If so, then let Rabbi Akiva say explicitly that this is what Rabbi Eliezer himself had taught him. The Gemara answers: He thought that it would not be proper to tell his teacher that he had forgotten his teaching, and therefore his initial attempt was to remind him indirectly.

The Gemara questions the reason for the halakha under discussion. What is the reason that the sprinkling of purifying water does not override Shabbat? Since it involves the mere moving of the liquid from the utensil in his hand to the body of the person seeking purification, why should it be forbidden on Shabbat? Let it at least override Shabbat on account of the mitzva of the Paschal lamb. Rabba said: The prohibition against sprinkling is a rabbinic decree that was instituted lest one take the utensil containing the purifying water and carry it a distance of four cubits in the public domain, thus violating an actual Torah prohibition. This is consistent with Rabba’s opinion in several other places in the Talmud that the Sages forbade the fulfillment of certain mitzvot due to a similar concern about carrying in the public domain.

The Gemara asks: At least according to Rabbi Eliezer, let us carry the purifying water even in the public domain, for Rabbi Eliezer said as a general rule that actions that facilitate the performance of a mitzva override Shabbat, even if they are not mitzvot themselves and involve transgression of Torah prohibitions. They say that there is room to distinguish between different situations: The rule that actions necessary to facilitate a mitzva override Shabbat only applies when the person himself is fit to fulfill the mitzva and the obligation to fulfill it is incumbent upon him. But here where the person himself is not fit to eat the Paschal lamb, as he is presently ritually impure, the obligation to fulfill the mitzva is not incumbent upon him, and therefore actions that would enable him to fulfill the mitzva do not override Shabbat.

Rabba said: According to the statement of Rabbi Eliezer that when a person is unfit no obligation is incumbent upon him, in the case of a healthy baby, one may heat water for him to strengthen him even further in order to circumcise him on Shabbat, as he is already now fit to be circumcised. But in the case of a sickly baby, one may not heat water for him to strengthen him in order to circumcise him, for owing to his sickliness he is not presently fit for the mitzva, and acts that facilitate a mitzva do not override Shabbat if the person is not currently fit for the mitzva.

Rava said: But if the baby is healthy, why does he need hot water to strengthen him? Rather, Rava said: All babies are considered sickly with respect to circumcision, as they all need to be washed with hot water. Therefore, both in the case of a healthy baby and in the case of a sickly baby, one may not heat water for him to strengthen him in order to circumcise him on Shabbat, even according to Rabbi Eliezer, as he is not presently fit for the mitzva.

Abaye raised an objection to Rabba’s distinction between someone who is currently fit for the mitzva and someone who is not, based on what was taught elsewhere in a baraita: An uncircumcised adult who did not circumcise himself before Passover is liable to the punishment of karet for having intentionally violated the mitzva to bring the Paschal lamb, as an uncircumcised person may not eat of the offering; this is the statement of Rabbi Eliezer. But here the person himself is not fit, for as long as he is uncircumcised he is not obligated to bring the Paschal lamb, and nonetheless the baraita is teaching that he is punished with karet. Apparently, the obligation is incumbent upon him even though he is presently unfit to perform the mitzva.

Rabba said in answer to this objection: Rabbi Eliezer holds that one may not slaughter the Paschal lamb or sprinkle its blood for someone who is ritually impure due to contact with a creeping animal because he is currently impure, even though he can immerse in a ritual bath and become pure by the night of Passover.