And in preparation for the rite of the red heifer, we intentionally impart impurity to the priest after he has already sanctified his hands and feet, as we learned in a mishna (Para 3:7): They would render the priest who burns the heifer ritually impure and immerse him immediately, to remove a misconception from the hearts of the Sadducees by means of a public display of disregard for their ruling. As the Sadducees would say: Only by those for whom the sun set was the heifer ritual performed. The Sadducees believed that it is prohibited for an impure priest who immersed that day to burn the red heifer until sunset, when the purification process is completed. The Gemara concludes: Since this impurity does not disqualify the sanctification of his hands and feet, learn from it that impurity does not disqualify sanctification of the hands and feet in general.

The Gemara responds: The service of the heifer is different, as one who immersed that day is not unfit for performing it, unlike any other rite. Likewise, impurity does not disqualify the sanctification of hands and feet preceding the service of the heifer. The Gemara asks: If so, why do I require that the priest sanctify his hands and feet at all for the service of the red heifer? The Gemara responds: We require that the service of the red heifer be similar to the service of offerings performed inside the Temple.

§ A dilemma was raised before the Sages: What is the halakha with regard to a priest who wishes to sanctify his hands and feet by dipping them in the Basin rather than letting the water run from it onto them? Must one say that the priest may not do so, since the Merciful One states: “And Aaron and his sons shall wash their hands and their feet from it” (Exodus 30:19), and not inside it? Or perhaps the priest may even use water still inside it.

Rav Naḥman bar Yitzḥak said: Come and hear a proof from a baraita: Or if a priest immersed in cave water and performed the service, his service is disqualified, since this is not adequate sanctification of the hands and feet. From the baraita one infers: But if he used water from the Basin in a manner similar to cave water, i.e., by immersing his hands, and performed the service, his service is valid.

The Gemara responds: No, it is possible that immersing one’s hands in the Basin is insufficient as well. Nevertheless, it was necessary for the baraita to mention cave water so that you shall not say: If one may immerse his entire body in cave water to purify himself, all the more so is it not clear that he may sanctify his hands and feet by immersing them in cave water? The baraita therefore teaches that despite being fit for immersion of the entire body, cave water is unfit for sanctification of the hands and feet.

§ Rabbi Ḥiyya bar Yosef says: The water in the Basin is disqualified by being left out, at different times of day for different rites. For rites that are permitting factors for an offering, i.e., that must be performed before the meat of the offering may be eaten, the water is disqualified at sunset, like the permitting factors themselves, which may be performed only during the day. For example, if a priest wishes to sprinkle an offering’s blood on the altar, he may not sanctify his hands and feet from the Basin unless it was sunk into its pit at sunset on the previous day, preventing the water from being disqualified. Similarly, for the burning of the offering’s limbs on the altar, which may be performed all night, the water in the Basin is disqualified at dawn, like the limbs themselves.

Rav Ḥisda says: Even for the performance of permitting factors, the water is disqualified only at dawn, as it is for the burning of the limbs. And Rabbi Yoḥanan says: Once one has sunk the Basin into its pit at the end of the day’s service, reconnecting the water in the Basin to flowing water to prevent it from being disqualified, he may not raise it up again the entire night.

The Gemara asks: Is this to say that if the Basin was not sunk before sunset the water inside is unfit for the night’s service as well? But doesn’t Rabbi Asi say that Rabbi Yoḥanan says in the name of Ilfa: With regard to a Basin that the priests did not sink into its pit at night, a priest sanctifies his hands and feet from it for the service of that night, and the next day he does not sanctify from it? Apparently, for purposes of the night’s service, the water in the Basin is not disqualified at sunset.

The Gemara responds: What does it mean when it says: He may not raise it up again? It means that he may not raise it to sanctify his hands and feet in preparation for the day’s service; but the water is fit for sanctification for the night’s service.

The Gemara asks: If so, this is the same as the opinion of Rabbi Ḥiyya bar Yosef, i.e., that for purposes of the day’s service the water in the Basin is disqualified at sunset, and for purposes of the night’s service it is disqualified at dawn.