lest one come to pick up the vessel in his hand and carry it four cubits in the public domain to a ritual bath. Abaye said to Rabba: If one has a pit full of water of a ritual bath in his courtyard, so that this decree should not apply, what is there to say? Rabba said to him: The Sages issued a decree against immersing vessels even in a pit of water in one’s own courtyard due to a pit situated in the public domain.

Abaye posed another challenge: This works out well with regard to Shabbat, but with regard to a Festival, when there is no prohibition against carrying from one domain to another, what is there to say? Rabba replied: The Sages issued a decree that it is prohibited to immerse a vessel on a Festival, due to the prohibition against immersing it on Shabbat.

The Gemara asks: And do we issue a decree in such a case? But didn’t we learn in the mishna: And Beit Shammai and Beit Hillel both agree that one may bring ritually impure water into contact with ritually pure water in stone vessels in order to purify the water. However, one may not immerse the impure water in a ritually impure vessel in order to purify the vessel at the same time. And if it is so that such a decree was issued, let us also decree here that bringing ritually impure water into contact with ritually pure water is prohibited due to the prohibition against immersing a ritually impure vessel in a ritual bath.

The Gemara rejects this challenge: And how can you understand that there is substance to this question? If he has other good, ritually pure, water to drink, why do I need to bring this ritually impure water into contact with the ritually pure water? Rather, one must say that he does not have suitable drinking water, and since he does not have other water, he is particularly careful about this water, so that it not become impure. Therefore, perforce, this must be an exceptional case, as the water became impure despite the precautions that were taken; and the Sages did not apply their decrees to unusual cases.

Abaye raised an objection from the following baraita: One may draw water from a spring or a ritual bath on a Festival with a ritually impure pail, and the pail becomes ritually pure because while being filled with water, the bucket is completely immersed in the ritual bath. And if it is so that the Sages issued such a decree, let us also decree here that it is prohibited to draw water on Festival with a ritually impure pail lest one come to immerse the pail by itself. Rabba answered: It is different there; since it is permitted for him to immerse the pail only by drawing water with it, he remembers that it is prohibited to immerse a vessel by itself, and therefore there is no reason to issue a decree.

Abaye raised an objection from a different baraita, in which it was taught: With regard to a vessel that was rendered ritually impure on the eve of a Festival, one may not immerse it on the Festival; however, if it became impure on the Festival itself, one may immerse it on the Festival. And if it is so that the Sages issued such a decree, let us also decree here that it is prohibited to immerse a vessel that became impure on a Festival due to the prohibition against immersing a vessel that became impure on the eve of a Festival. Rabba answered: Contracting ritual impurity on a Festival, when all are ritually pure, is an uncommon occurrence, and the general principle is that in the case of an uncommon occurrence, the Sages did not issue a decree as a preventive measure.

Abaye raised yet another objection from the following baraita: With regard to a vessel that was rendered ritually impure by a primary source of impurity, one may not immerse it on a Festival. However, if it was rendered impure only by a derivative source of impurity, meaning that the vessel came into contact with an object that was rendered impure by a primary source of impurity, so that the object has the status of first-degree ritual impurity and confers upon the vessel the status of second-degree ritual impurity, a type of impurity that applies to vessels only by rabbinic decree; in such a case, one may immerse the vessel on a Festival. And if it is so that the Sages issued such a decree, let us also decree here that it is prohibited to immerse this, a vessel rendered impure by a derivative source of impurity, due to the prohibition to immerse that, a vessel rendered impure by a primary source of impurity.

Rabba replied: Where do you find a case where people are particular about purifying a vessel that contracted ritual impurity from a derivative source of impurity? It is only in one situation, namely, with regard to priests, since they eat teruma, and teruma contracts ritual impurity even from a vessel that came into contact with only a derivative source of impurity. An ordinary person, who eats non-consecrated produce, does not go to the trouble of purifying such a vessel, since regular produce contracts ritual impurity only from a vessel that came into contact with a primary source of impurity, but not from a vessel that came into contact with a derivative source of impurity. And as for priests, the general principle is that priests are vigilant; they are careful not to allow their vessels to become impure. Therefore, impurity in the case of priests is considered a rare occurrence, with regard to which the Sages did not issue a decree.

The Gemara further suggests: Come and hear a different proof, as Rav Ḥiyya bar Ashi said that Rav said: A menstruating woman who has no ritually pure clothes to wear after she immerses herself in a ritual bath to purify herself, as all her clothes had become impure, and it is Shabbat or a Festival, when she is unable to immerse them, may employ an artifice to circumvent the prohibition and immerse herself in her clothes. She is permitted to purify herself, and when she immerses herself while wearing her garments, they become purified at the same time. And if it is so that the Sages issued such a decree, let us also decree that it is prohibited for the woman to immerse herself in her clothes lest she come to immerse the clothes by themselves.

The Gemara answers: It is different there; since it is permitted for her to immerse the clothes only by wearing them as garments, she remembers that it is prohibited to immerse them by themselves and will not come to violate this prohibition.

Apropos Rabba’s view that one may not immerse a vessel on Shabbat lest he come to carry it four cubits in the public domain, Rav Yosef said that it is prohibited to immerse a vessel on Shabbat for a different reason: It is a decree issued by the Sages as a preventive measure due to the prohibition against wringing. After immersing certain items, such as clothes, one might come to wring them, and this is prohibited on Shabbat and Festivals as a subcategory of the biblically prohibited labor of threshing.

Abaye said to Rav Yosef: This works out well with regard to vessels that are fit for wringing, such as clothes, but with regard to vessels that are not fit for wringing, what is there to say? Rav Yosef said to him: The Sages issued a decree against these vessels, which cannot be wrung, due to those vessels, which can be wrung. Abaye raised against Rav Yosef all of these objections that he had raised against Rabba, in an attempt to prove that the Sages did not issue such a decree, and Rav Yosef answered him as we answered in the name of Rabba.

Rav Beivai said a different reason: The prohibition against immersing a vessel on a Festival is a decree issued by the Sages lest one come to delay the immersion of his impure vessels. Were the Sages to permit him to immerse vessels on a Festival, he might delay immersing all of his impure vessels until the Festival, when he has more free time; and were he to leave ritually impure vessels in his possession for a lengthy period, he might come to defile items that must be kept ritually pure, such as teruma. The Gemara comments: It is taught in a baraita in accordance with the opinion of Rav Beivai: With regard to a vessel that became ritually impure on the eve of a Festival, one may not immerse it on a Festival, due to a decree lest he come to delay and keep impure vessels in his home in order to immerse them on the Festival.

Rava said yet a different reason: It is prohibited to immerse a vessel on Shabbat because it looks as if he is repairing the vessel. Since the vessel was previously unfit for use, and the act of immersion renders it usable, this is similar to the repair of a vessel, which Torah law proscribes on Shabbat and Festivals. The Gemara challenges this understanding: If so, a person should likewise be prohibited to immerse himself, because it looks as if he is repairing himself through purification. The Gemara answers: A person undergoing immersion looks as if he is cooling himself. Since it is not clearly evident that he is immersing in order to purify himself, as he might be bathing for his pleasure, there is no reason to prohibit the immersion.

The Gemara challenges this explanation: This works out well in a case where he immerses himself in good, clean water, in which it would be a pleasure to bathe; but if he immerses himself in bad, murky water, as the water of a ritual bath is not always sufficiently clean, what is there to say? Rav Naḥman bar Yitzḥak said: Even in that case, his actions do not prove that his intention is to purify himself, as sometimes a person comes home