In the name of Rabbi Sheila they said: A groom is exempt from the mitzva of Shema, but the groomsmen and all the members of the wedding party are obligated.

§ It is taught in a baraita: Rabbi Ḥananya ben Akavya said: With regard to scribes of Torah scrolls, phylacteries, and mezuzot, they themselves, and the merchants who sell them, and the merchants who purchase them from the first merchants and sell them to others, and all who are engaged in the labor of Heaven, which comes to include the sellers of the sky-blue dye for ritual fringes, are all exempt from the mitzva of reciting Shema and from prayer and from donning phylacteries and from all mitzvot that are mentioned in the Torah while they are engaged in that labor. This statement comes to fulfill the statement of Rabbi Yosei HaGelili, as Rabbi Yosei HaGelili would say: One who is engaged in a mitzva is exempt from another mitzva.

The Sages taught in a baraita: Travelers who travel during the day are exempt from the mitzva of sukka during the day and are obligated at night. Travelers by night are exempt from the mitzva of sukka at night and obligated during the day. Travelers both during the day and at night are exempt from the mitzva of sukka both during the day and at night. Those who travel for a matter of mitzva are exempt both during the day and at night, because they are preoccupied with the mitzva, even if they are not traveling at night, as in this recurring incident involving Rav Ḥisda and Rabba bar Rav Huna. The Gemara relates: When they would enter the house of the Exilarch on the Shabbat of the Festival to hear his Festival homily, they would sleep on the bank of the Sura River and not in a sukka. They said in explanation: We are ones on the path to perform a mitzva and are exempt from the mitzva of sukka.

The Sages taught in a baraita: Guardians of the city who guard during the day are exempt from the mitzva of sukka during the day and are obligated at night. Guardians of the city at night are exempt from the mitzva of sukka at night and are obligated during the day. Those who guard the city both during the day and at night are exempt from the mitzva of sukka both during the day and at night.

Guardians of gardens and orchards are exempt from sukka both during the day and at night. The Gemara asks: And let them establish a sukka there in the garden and reside there. Why are they exempt from the mitzva of sukka? Abaye said: The reason for the exemption is the verse: “In sukkot shall you reside” (Leviticus 23:42), which the Sages interpreted to mean: Reside as you dwell in your permanent home. Since preparing a sukka that is a fully equipped dwelling in the orchard far from his house would involve considerable exertion, the mitzva does not apply to him.

Rava said: A breach summons the thief. If the guardian builds a sukka, thieves will know where the guardian is located in the field and they will enter the field elsewhere. The exemption of the watchman from the mitzva of sukka prevents that situation. The Gemara asks: What is the practical difference between the two reasons given? The Gemara answers: There is a difference between them in a case where he is guarding a pile of fruit, which can be guarded from inside the sukka; therefore, according to Rava, in that case the guard would be obligated in the mitzva of sukka. However, since the sukka in the orchard is not like a fully equipped home, in Abaye’s opinion he would still be exempt in that case.

§ It is stated in the mishna: The ill and their caretakers are exempt from the mitzva of sukka. The Sages taught in a baraita: The ill person that they said is exempt from sukka is not only an ill person whose condition is critical, but even an ill person whose condition is not critical, and even one who feels pain in his eyes, and even one who feels pain in his head. Rabban Shimon ben Gamliel said: One time I felt pain in my eyes in Caesarea, and the esteemed Rabbi Yosei ben Ḥalafta permitted me and my attendant to sleep outside the sukka.

The Gemara relates a similar tale: Rav permitted Rav Aḥa Bardela to sleep beneath a canopy in the sukka due to the biting flies [baki]. He permitted this although the canopy was more than ten handbreadths high and in sleeping beneath it he did not fulfill his obligation. Rava permitted Rabbi Aḥa bar Adda to sleep outside the sukka due to the foul odor of the earth [gargishta] floor of the sukka.

The Gemara comments: Rava conforms to his line of reasoning, as Rava said: One who suffers in the sukka is exempt from the mitzva of sukka. The Gemara asks: But didn’t we learn in the mishna that the ill and their caretakers are exempt from the mitzva of sukka? By inference, with regard to an ill person, yes, he is exempt; with regard to one who suffers, no, he is not exempt. The Sages say: With regard to an ill person, he and his caretakers are exempt; however, with regard to one who merely suffers in the sukka, he is exempt but his caretakers are not.

§ The mishna continues: One may eat and drink in the framework of a casual meal outside the sukka. The Gemara asks: And how much food is considered a casual meal? Rav Yosef said: It is two or three egg-bulks of bread. Abaye said to him: But often, doesn’t a person suffice with that measure of food, and then its legal status is that of a formal meal? Rather, Abaye said: A casual meal is like the measure that a student of the academy of Rav tastes and then enters the study hall to hear the lecture.

The Sages taught in a baraita: One may eat a casual meal outside the sukka, but one may not take even a brief nap outside the sukka. The Gemara asks: What is the reason for this distinction? After all, sleeping in the sukka is an obligation just as eating in the sukka is an obligation. Rav Ashi said: It is prohibited to nap outside the sukka due to a decree lest he fall into a deep sleep.

Abaye said to him: But with regard to that halakha which is taught in a baraita: A person may take a brief nap while donning phylacteries but substantial sleep is not permitted. Let us be concerned in that case as well lest he fall into a deep sleep. Rav Yosef, son of Rav Illai, said: There is no concern with regard to phylacteries, as it is a case where one assigns responsibility for ensuring that his sleep will not be prolonged to others.

Rav Mesharshiyya strongly objects to Abaye’s statement: Your guarantor, who ensures that you do not sleep too long, requires a guarantor to ensure that he does not do the same. Rather, Rabba bar bar Ḥana said that Rabbi Yoḥanan said: We are dealing with a case where he places his head between his knees, a position that does not lend itself to deep sleep. Rava said: Neither with regard to sukka nor with regard to phylacteries is there concern lest he fall into a deep sleep. Taking a brief nap outside the sukka is prohibited because there is no concept of substantial duration with regard to sleep, i.e., there is no halakhic difference between a brief nap and a longer-lasting sleep. Depending on circumstances, sleep of any duration can be considered substantial and is therefore prohibited outside a sukka.

The Gemara comments that it is taught in one baraita: A person may take a brief nap with phylacteries, but substantial sleep is not permitted. And it was taught in another baraita: Both substantial sleep and a brief nap are permitted. And it was taught in another baraita: Neither substantial sleep nor a brief nap is permitted. The Gemara explains that this is not difficult: This baraita, where it is taught that even a brief nap is prohibited, is in a case where one holds the phylacteries in his hands. It is prohibited to sleep at all lest he drop them. That baraita, where it was taught that a brief nap is permitted, is in a case where the phylacteries are placed on his head. There is no concern during a brief nap lest he break wind or experience a seminal emission. During deep sleep, that is a concern. That third baraita, where it was taught that even substantial sleep is permitted with phylacteries, is in a case where he removes the phylacteries and spreads a cloth over them and sleeps alongside them.

The Gemara asks: And how much is the duration of a brief nap? Rami bar Yeḥezkel taught: It is equivalent to the time required for walking one hundred cubits. The Gemara comments: That is also taught in a baraita: One who sleeps with phylacteries and experiences a seminal emission grips the strap of the phylacteries to remove them