The Gemara responds: The difference between them is that according to Rabbi Ḥiyya bar Yosef, if the water is raised at any point throughout the night, it is disqualified for sanctification prior to the day’s services. According to Rabbi Yoḥanan, the water is not disqualified unless the Basin is raised at the break of dawn, but the Sages issued a rabbinic decree of sinking the Basin into its pit all night ab initio, so that it would not be raised at dawn accidentally.

The Gemara asks: Does Rabbi Yoḥanan really hold that the Basin must be sunk all night? But doesn’t Rabbi Yoḥanan say: If a priest sanctified his hands and feet in preparation for the removal of the ashes before dawn, then the next day he does not need to sanctify them again, as he already sanctified them at the beginning of the day’s service? Evidently, the Basin is raised before dawn.

The Gemara elaborates: Granted, according to Rava, who interprets that statement in accordance with the opinion of Rabbi Elazar, son of Rabbi Shimon, that sanctification of the hands and feet is not disqualified overnight (see 20a), this statement that the Basin must be sunk all night is in accordance with the opinion of Rabbi Yehuda HaNasi, who holds that sanctification of the hands and feet is disqualified at dawn. Accordingly, he holds that the water in the Basin is disqualified as well.

But according to Abaye, who interprets that statement in accordance with the opinion of Rabbi Yehuda HaNasi, the first statement of Rabbi Yehuda HaNasi is difficult to reconcile with this other statement of Rabbi Yehuda HaNasi: What is different there that one must sink the Basin all night, and what is different here, with regard to sanctification prior to removal of the ashes, that one does not need to sink it?

The Gemara responds: There is no contradiction. Prior to removal of the ashes, one raises the Basin and then sinks it again so that it will not remain raised at dawn and render the water disqualified.

The Gemara asks: If so, why does Rabbi Yoḥanan say that the priest does not sanctify his hands and feet again the next day? If the water has not been disqualified, why would the priest need to avoid sanctifying his hands and feet with it? The Gemara responds: Rabbi Yoḥanan means to say that he does not need to sanctify them again for service on the same day, not that he is prohibited from doing so.

The Gemara asks: Is this to say that according to Rabbi Yoḥanan, if one raised the Basin at night and sank it again before dawn, it remains fit for sanctification prior to performing the offering’s permitting factors that day? If so, Rabbi Yoḥanan’s opinion is the same as that of Rav Ḥisda.

The Gemara responds: The difference between them is that according to Rav Ḥisda, there is no mitzva of sinking the Basin into its pit throughout the night, whereas Rabbi Yoḥanan holds that there is a mitzva of sinking the Basin into its pit all night ab initio.

The Gemara raises an objection to the opinion of Rav Ḥisda from a mishna (Tamid 28b): The priests would not see the priest performing the removal of the ashes, nor would they hear his voice. Rather, they were unaware of his actions until they would hear the sound of the wood with which ben Katin made a mechanism for sinking the Basin into water during the night. And when they heard the sound of the mechanism, they would say to each other: The time for sanctifying hands and feet from the Basin has come. The Gemara asks: What, is it not that they heard the mechanism raising the Basin? Apparently, the mechanism would sink it during the night, in contradiction to the opinion of Rav Ḥisda, who holds that there was no need to sink it overnight.

The Gemara responds: No, they heard the mechanism sinking the Basin, which had been raised all night. The Gemara asks: If the mechanism were sinking it, would its sound be audible? No mechanism is necessary to lower the Basin; it can simply be lowered with a chain. The Gemara responds: The priest would still sink it by using a wheel, which would make a sound.

The Gemara presents another version of the answer: The priest would deliberately sink it by its wheel so that its sound would be audible, and the other priests would hear and come to begin the service. The Gemara asks: But wasn’t there Gevini the crier, who would notify the priests of the beginning of the service? The Gemara responds: They would make two conspicuous markers for the beginning of the service: The sound of the wheel and the crier. Anyone who heard from this marker would come, and anyone who heard from that marker would come.

§ Having mentioned a halakha earlier (19b), the Gemara addresses the matter itself: Rabbi Yosei, son of Rabbi Ḥanina, says: With regard to any Basin that does not contain enough water for four priests to sanctify their hands and feet from it, the priests may not sanctify their hands and feet with it, as it is stated: “That Moses and Aaron and his sons might wash their hands and their feet from it” (Exodus 40:31).

The Gemara raises an objection from a baraita: The priests may sanctify their hands and feet from all vessels, whether they can hold a quarter-log of water