and the priests are troubled by being forced to circumvent it, as it is prohibited for them to become ritually impure from contact with a corpse. There was suspicion, but no certainty, that a corpse was buried there. Therefore, they were unable to definitively determine its status. Rabbi Shimon said: Is there a person who knows that there was a presumption of ritual purity here? Is there anyone who remembers a time when this place was not considered ritually impure, or that at least part of it was considered to be ritually pure? An Elder said to him: Here ben Zakkai planted and cut the teruma of lupines. In this marketplace Rabbi Yoḥanan ben Zakkai, who himself was a priest, once planted lupines that were given to him as teruma. On that basis, the conclusion can be drawn that it was definitely ritually pure. Rabbi Shimon, like Jacob, also did so and took steps to improve the city and examined the ground (Tosafot). Everywhere that the ground was hard, he pronounced it ritually pure as there was certainly no corpse there, and every place that the ground was soft, he marked it indicating that perhaps a corpse was buried there. In that way, he purified the marketplace so that even priests could walk through it.

A certain Elder said in ridicule and surprise: Ben Yoḥai purified the cemetery. Rabbi Shimon got angry and said to him: Had you not been with us, and even had you been with us and were not counted with us in rendering this ruling, what you say is fine. You could have said that you were unaware of my intention or that you did not agree or participate in this decision. Now that you were with us and were counted with us in rendering this ruling, you will cause people to say that Sages are unwilling to cooperate with one another. They will say: If competing prostitutes still apply makeup to each other to help one another look beautiful, all the more so that Torah scholars should cooperate with each other. He directed his eyes toward him and the Elder died. Rabbi Shimon went out to the marketplace and he saw Yehuda, son of converts, who was the cause of this entire incident. Rabbi Shimon, said: This one still has a place in the world? He directed his eyes toward him and turned him into a pile of bones.

MISHNA: There are three things a person must say in his home on Shabbat eve at nightfall and not before. The mishna elaborates: He should ask the members of his household, have you tithed the crop that required tithing? Have you placed the eiruv for joining the courtyards and joining the Shabbat borders? If you have done so, light the lamp in honor of Shabbat. The Sages stated a principle: If the time arrives on Friday when there is uncertainty whether it is nightfall and uncertainty whether it is not yet nightfall, one may not tithe the crop that has definitely not been tithed, and one may not immerse ritually impure vessels in a ritual bath to render them ritually pure, and one may not light the Shabbat lights. However, one may tithe demai, doubtfully tithed produce, which must be tithed due to mere suspicion. And one may place an eiruv and insulate the hot water to be used on Shabbat.

GEMARA: The Gemara attempts to clarify: From where are these matters, that one must ask these questions in his home at nightfall of Shabbat, derived? Rabbi Yehoshua ben Levi said: As the verse said: “And you shall know that your tent is in peace; and you shall visit your habitation, and shall not sin” (Job 5:24). From here it is derived that one should visit his habitation, i.e., ask in his home, so that he will not come to sin. Rabba bar Rav Huna said: Although the Sages said that there are three things a person should, indeed he is required to, say in his home on Shabbat eve at nightfall, one must say them calmly so that the members of his household will accept them from him. If he says them harshly, his family members may mislead him and cause him to sin. Rav Ashi said: I did not hear this halakha of Rabba bar Rav Huna, but I fulfilled it based on my own reasoning.

The Gemara asks: This mishna itself is difficult, as it contains an internal contradiction. On the one hand, you stated initially that there are three things a person must say in his home before Shabbat at nightfall, and this means: At nightfall, i.e., before nightfall, yes, he should say those things; when there is uncertainty whether it is nightfall and uncertainty whether it is not yet nightfall, no, he should not say them. Even if one were to ask then, it is no longer permitted to correct these matters. And then it taught: When there is uncertainty whether it is nightfall and uncertainty whether it is not yet nightfall, one may place an eiruv. One may correct the situation even then. Why did the mishna restrict asking these questions to an earlier time?

Incidentally, prior to answering this question, the Gemara lists all of the other halakhot in tractate Shabbat stated by the Sage who answers the question, with the mnemonic: Self, pruning, bird, cord, silk.

Rabbi Abba said that Rabbi Ḥiyya bar Ashi said that Rav said: This is not difficult and there is no contradiction here. Here, at the beginning of the mishna, where it indicates that the eiruv can only be placed while it is still day, it is referring to the joining of Shabbat boundaries, which is based on a Torah law. Therefore, one must place this eiruv while it is definitely day. And here, where the mishna said that it is permitted even when it is uncertain whether or not it is already nighttime, it is referring to the joining of courtyards, which is more lenient and based merely on a stringency.

In connection to this, the Gemara cites the halakha that Rava said in order to emphasize the rabbinic aspect of the halakhot of eiruv: One to whom two people said: Go and place an eiruv, a joining of courtyards (Rabbeinu Ḥananel), for us. For one of them he placed an eiruv while it was still day, and for one he placed an eiruv at twilight, when it is uncertain whether it is day or night. The one for whom he placed an eiruv while it was still day had his eiruv eaten during twilight, and the one for whom he placed an eiruv during twilight had his eiruv eaten after nightfall. The principle is as follows: Whether or not an eiruv takes effect is determined at the moment that Shabbat begins. If one placed the eiruv beforehand, and it remains intact at the moment Shabbat begins, the eiruv is in effect. However, if the eiruv that was placed at the appropriate time was eaten during twilight, it is problematic. Twilight is a period of uncertainty. There is uncertainty whether it is day, and consequently the eiruv was not in place at the moment that Shabbat began, or whether it is night, and it was in place. In the latter case, there is still uncertainty as to whether or not the eiruv was in place prior to Shabbat, so that it could take effect at all. In that case, Rava ruled that both of them acquired the eiruv.

The Gemara is surprised by this: Whichever way you look at it, this ruling is difficult. If the twilight period is considered day, let the latter one acquire his eiruv, but let the first one not acquire his because his eiruv was eaten while it was still day. And if the twilight period is night, let the first one acquire his eiruv, but let the latter one not acquire his eiruv because his was not placed before Shabbat. In any event, it is impossible for the eiruv in both of these cases to be valid. The Gemara answers this according to Rava’s position: The status of twilight is uncertain, as it is unknown whether it is day, or night, or both, and uncertainty in the case of a rabbinic ordinance is ruled leniently. Therefore, in both cases the eiruv is acquired.

And Rava said: Why did they say that one may not insulate hot water even in something that does not add heat, but only retains the pre-existing heat, from nightfall on Friday? It is a decree lest one come to boil the pot on Shabbat. Abaye said to him: If so, if it is due to concern that one may boil it, then during twilight we should also issue a decree and prohibit insulating in something that does not add heat. Rava said to him: During twilight, there is no reason to be concerned because at that time most pots are boiling, as they have just been taken off of the fire. Later at night the pots cool down and it is conceivable that one may come to boil them in order to restore the heat.

And Rava said: