1) HE SHOULD SEARCH HIS ACTIONS
QUESTION: The Gemara says that if a person is suffering, he should search his deeds for possible sins. If he does not find any sins, he should attribute the suffering to the sin of Bitul Torah.
How can he attribute the suffering to Bitul Torah, if he just searched his actions and found no sins (that is, not even the sin of Bitul Torah)?
RASHI (DH Pishpesh v'Lo Matza) explains that he did not find any sin deserving of such a severe punishment. However, our question remains. If Bitul Torah does not warrant such severe punishment, how can it be the cause of his suffering?
(a) The small amount of Bitul Torah that he was guilty of may have caused him to misunderstand a Halachah entirely. Therefore, he is held accountable for his violation of that Halachah, because "Shigegas Talmud Olah Zadon" -- "[Misdeeds that result from] mistakes in learning are considered intentional [misdeeds]" (Avos 4:13). (VILNA GA'ON; OLELOS EFRAIM #93)
(b) Torah learning protects a person from afflictions that he deserves for his past sins (Sotah 22a). If he searched his actions and found no new sins to which he can attribute his afflictions, he should attribute them to Bitul Torah. Even a small amount of Bitul Torah will causes him to lose his protection from the afflictions due to him for past sins. (MISHNAS CHACHAMIM, based on the ALSHICH)
(c) When the Gemara says that "one does not find any sins," it means that he did not find any sins that matched his afflictions (i.e. he found no "Midah k'Neged Midah" relationship between his sins and his afflictions). The same way that learning Torah vitalizes one's entire body (Eruvin 54a), Bitul Torah causes afflictions to come upon one's entire body. Therefore, he may attribute any afflictions to Bitul Torah. (BIRKAS ROSH)
2) AFFLICTIONS ATONE FOR ALL OF ONE'S SINS
QUESTION: The Gemara derives from the law of the emancipation of slaves that afflictions atone for all of one's sins. The Gemara proves through a Kal v'Chomer that if a slave is set free when his master dislodges his tooth or eye, then certainly when a person's entire body is afflicted, he becomes "free" from his sins.
Afflictions come upon a person because he deserves them as punishment for his sins. In contrast, the slave's loss of a tooth or an eye is not an affliction that he deserves. How, then, can we derive from the law of a slave that even when a person deserves afflictions, they atone for his sins?
(a) If a slave hits his master and his master hits him back and knocks out a tooth or an eye, does the slave go free? We see from our Gemara that he does go free, even though he instigated the master's blow. Therefore, the Gemara's Kal v'Chomer is accurate: if a slave goes free when he loses a tooth or an eye even though he instigated his master's rage, then certainly a person goes free when his entire body is afflicted, even though he instigated Hash-m's rage. (RAV HAI GAON, ROGATCHOVER GA'ON in Teshuvos Tzafnas Pane'ach)
(b) Why does a slave go free with the loss of a tooth or an eye? The Midrash explains that Cana'an, the father of all slaves (see Bereishis 9:25), sinned with his mouth and his eyes, as it says, "And [he] saw... the nakedness of his father, and he told his two brothers..." (Bereishis 9:22; see Rashi there). If a slave loses a tooth or an eye, that serves as an atonement for the sin of Cana'an and he is released from slavery.
However, according to this understanding, a slave should be freed only when he loses both a tooth and an eye! Why are slaves released after losing either one? The answer is that Hash-m has mercy on the slave and lets him go free with the loss of either one.
Based on this, the Gemara's Kal v'Chomer may be understood as follows. If the loss of just a tooth or an eye of a slave atones for the sin of Cana'an, then afflictions on one's entire body certainly atone for one's sins.
3) HALACHAH: LEAVING SOMEONE BEHIND IN THE SYNAGOGUE
OPINIONS: The Beraisa quotes Aba Binyamin who says that when two people enter a synagogue to pray, and one finishes before the other and departs from the synagogue, leaving his friend alone, his prayers are torn up in heaven.
When exactly is it prohibited to leave a synagogue when one other person is still praying there?
(a) RABEINU CHANANEL (cited by Talmidei Rabeinu Yonah) writes that this Halachah applies only at night, in synagogues in the fields (outside of a populated area). There is a concern that the Mazikin (demons) may harm a person who returns from the synagogue alone.
(b) The RIF, TOSFOS HA'ROSH, and TUR rule that this Halachah applies at night even in the city, because it is dangerous to return home alone at night. (Perhaps in their times, the streets at night were more dangerous than in the time of Rabeinu Chananel.)
(c) Another reason is cited in the name of Rabeinu Chananel. Since the Gemara later (6a) says that there is a higher level of Shechinah present with two people who pray together than with one, when a person leaves his friend who is still praying he causes the Shechinah to depart. According to this, it would not be permitted to leave another person behind by himself even during the day, and even within the city.
(d) In a similar vein, TALMIDEI RABEINU YONAH explain that if a person is left alone to pray, he will be afraid and he will be unable to concentrate properly. According to this reason, too, it is not permissible to leave another person behind by himself even during the day, and even within the city.
HALACHAH: The SHULCHAN ARUCH (OC 90:15) rules like the Rif, Rosh, and Tur (b), who say that one may not leave his friend praying alone at night, either outside or inside the city.
The REMA adds that it is a trait of the righteous to remain with the individual who is still praying even during the day. TOSFOS (DH ha'Mispalel) mentions that that was indeed the practice of the RI.
There are two exceptions to this Halachah. The first exception is when the person starts to pray after the Tzibur starts. By doing so, he shows that he does not mind being left alone (otherwise, he would not have started to pray, since he realizes that everyone will finish before him and leave him behind). The second exception is when the person takes a long time because he adds additional prayers to his Shemoneh Esreh. Again, he shows that he does not mind being left alone.