GEMARA: We learned in the mishna that one may not read the names of his guests or the appetizers served in his meal from a written list. The Gemara asks: What is the reason for this prohibition? Rav Beivai said: It is a decree lest one erase something that is written on the list if he regrets inviting a particular guest or changes his mind about a particular dish. Abaye said: It is a decree lest one read regular business documents.

The Gemara asks: What is the practical difference between them? The Gemara answers: There is a difference between them in a case in which the writing is on a wall and it is raised higher than a person can reach. According to the one who says that the decree was made lest one erase something from the list, in a case such as this we are not concerned about erasure because one cannot even reach the writing. But according to the one who says that the decree was made lest one read business documents, we are still concerned in this case.

The Gemara asks: And according to the one who says that the decree was made lest one erase, we should also be concerned lest one read business documents. And furthermore, are we really not concerned lest one erase when the writing is high up? But wasn’t it taught in a baraita that one may not read by the light of a lamp on Shabbat lest one adjust the lamp toward oneself; and Rabba said: Even if the lamp was two statures of a person high, and even as high as two plow handles, and even if it was as high as ten houses one atop the other, one may not read by its light. This clearly demonstrates that when we are concerned that one may violate halakha, we do not distinguish between situations in which such a violation is more or less likely.

Rather, there is a difference between them in a case in which the writing is on a wall and it is low down. According to the one who says that the reason for the decree is lest one erase, in a case such as this we are concerned because one can easily reach the writing and erase it. However, according to the one who says that the decree was made lest one read business documents, we are not concerned because a wall will not be confused with a document, and reading from the wall will not cause one to then read business documents.

The Gemara asks further: And according to the one who says that the concern is lest one read, we should also be concerned lest one erase. Rather, there is a practical difference between them in a case where the writing is engraved on a tablet or on a board. According to the one who says that the concern is lest one erase, in a case such as this we are not concerned. Since the writing is not in ink, there is no concern that he will erase it. According to the one who says that the concern is lest one read business documents, we are concerned. The style of writing is irrelevant in terms of the likelihood that one will end up reading business documents.

The Gemara asks further: According to the one who says that the concern is lest one erase, we should also be concerned lest one read business documents. And if you say: A tablet or a board will not be confused with a document, but wasn’t it taught explicitly in a baraita: One may count how many guests will sit inside, and how many guests will sit outside, and how many portions he will place before them from writing that is on the wall, but not from writing that is on a tablet or a board?

The Gemara attempts to clarify this: What are the circumstances of the case described in this statement? If you say that it was written in ink, what is the difference here, when the writing is on a wall, and what is the difference here, when the writing is on a tablet? Rather, is it not a case of a list that has been engraved, and nonetheless it teaches that one may read from writing that is on the wall but not from writing that is on a tablet or a board?

Rather, we should actually explain that the writing was on a wall and was raised. And with regard to what was difficult for you, based on Rabba’s statement that prohibited reading by candlelight on Shabbat regardless of the height of the candle, which presumably means that in our case, too, we should be stringent regardless of the height of the writing, that statement of Rabba is the subject of dispute between tanna’im, as it was taught in a baraita: One may count one’s guests and one’s appetizers from memory, but not from a written list. Rabbi Aḥa permits reading from a written list that is on a wall.

The Gemara attempts to clarify this: What are the circumstances in which Rabbi Aḥa permits this? If you say that it is written below, low down on the wall, we should be concerned that perhaps one will erase it. Rather, is it not referring to a case in which it is written and the location of the writing is raised such that it is high up on the wall, and conclude from this that the statement of Rabba is the subject of dispute among the tanna’im? The Gemara concludes: Indeed, conclude from this that it is so.

The Gemara comments that in this matter, these tanna’im are like those tanna’im, who also argued over the same principle, as it was taught in a baraita: One may not look in a mirror on Shabbat lest one see a hair hanging and pluck it. Rabbi Meir permits looking in a mirror that is fixed on a wall.

The Gemara questions Rabbi Meir’s leniency: What is different about a mirror that is fixed on a wall? In that situation we say that, in the meantime, while one goes to bring scissors or another appliance to cut one’s hair, one will remember that it is Shabbat and that it is prohibited to cut hair. If so, with regard to a mirror that is not fixed on a wall, we can also say that in the meantime one will remember.

Rather, here we are dealing with a metal mirror, and it is as Rav Naḥman said that Rabba bar Avuh said, for Rav Naḥman said that Rabba bar Avuh said: For what reason did the Sages say that a metal mirror is prohibited for use on Shabbat? Because a person may remove hanging hairs with it, meaning that one may use the sharp edge of the mirror itself to cut the hairs. If the mirror is permanently set on the wall, we are not concerned that one will do this. This is similar to the view that one may read writing that is high up on a wall because it is impractical to erase the writing.

The Sages taught in a baraita: With regard to writing that is under a picture or under graven images [deyokenaot], it is prohibited to read it on Shabbat lest one end up reading business documents. And with regard to an idolatrous image itself, even on a weekday it is prohibited to look at it, because it says: “Do not turn toward idols [al tifnu el ha’elilim] or make yourselves molten gods, I am the Lord your God” (Leviticus 19:4). The Gemara asks for clarification: What is the biblical derivation? How does this verse indicate that one may not look at an idolatrous image? Rabbi Ḥanin said: Do not push God [al tefannu El] out of your mind by looking at these images (Arukh).

We learned in the mishna that a person may draw lots with one’s children and family members at the table on Shabbat to see who will receive which meal portion. The Gemara infers: With one’s children and family members, yes, it is permitted, but with another person it is not. What is the reason for this? The Gemara explains that it is as Rav Yehuda said that Shmuel said, for Rav Yehuda said that Shmuel said: Members of a group who are eating together on Shabbat or on a Festival and who are particular with each other that no one receive a larger portion than anyone else are in violation of the prohibitions of measuring, and weighing, and counting merchandise on Shabbat or a Festival, and they are also in violation of the prohibition against lending and repaying on a Festival.