QUESTION: The Beraisa explains that the merit of a Mitzvah is compared to candlelight, and the merit of learning Torah is compared to daylight. Just as candlelight provides only a temporary protection from the dangers of the dark, a Mitzvah protects a person only temporarily. The merit of learning Torah, on the other hand, is like daylight; just as daylight is a permanent form of protection (for the sun consistently rises each day), the Torah is a permanent form of protection for a person.
In the Gemara's conclusion, Rava explains that both Torah and Mitzvos protect a person from Yisurin, physical afflictions in this world, both during the time he is involved in them (learning Torah or performing a Mitzvah) and afterwards. The Torah has the additional property that during the time a person is learning, it also protects him from the Yetzer ha'Ra (that is, it affords spiritual protection as well as physical protection).
The Gemara's conclusion seems to contradict the statement of the Beraisa. The Beraisa says that the difference between the merit of Torah and the merit of a Mitzvah is that the merit of Torah provides a more permanent form of protection. According to Rava, however, both the Torah and a Mitzvah offer protection from Yisurin even when a person is not involved with them. Only with regard to protection from the Yetzer ha'Ra do the two differ: a Mitzvah does not provide any protection, while the Torah does.
With regard to what form of danger does the Beraisa state that a Mitzvah provides protection but its protection is less than that provided by the Torah? (TOSFOS DH Mitzvah)
(a) The MAHARSHA answers that a Mitzvah's protection exists only in Olam ha'Zeh, this world. The Torah, in contrast, provides protection for the Neshamah even after the person leaves this world. It protects the Neshamah from the Yisurin of Din, judgement, in Olam ha'Ba. (See Chagigah 27a: "The fire of Gehinom has no power over those who learn Torah"; see also Chagigah 15b, and RASHASH and NETZIV here.) In this sense the protection of the Torah is more permanent than the protection of a Mitzvah.
TOSFOS, however, does not accept this answer, perhaps because the Beraisa continues and says that there is another explanation for the difference between Torah and Mitzvos -- that sin can extinguish the merit of a Mitzvah (l'Asid la'Vo; see Rashi and Tosfos) but it cannot extinguish the merit of Torah. What does the Beraisa mean when it says that a sin can extinguish a Mitzvah? If a person performs a Mitzvah, how can he lose reward for it by doing an Aveirah? The Beraisa must mean that the reward of the Mitzvah cannot overpower the necessity for punishment for the Aveirah. Consequently, the person will be punished for the Aveirah despite the fact that he did a Mitzvah. With regard to Torah, however, the Torah he learned will protect him to some extent from punishment for his Aveiros. Since the "Davar Acher" of the Beraisa expresses this difference between Torah and Mitzvos, this cannot be the difference expressed by the first part of the Beraisa. Perhaps the Maharsha understands that the "Davar Acher" indeed expresses the same idea as the first part of the Beraisa but merely in different terms. (Tosfos considered this interpretation improbable and thus did not accept it.)
(b) The CHAFETZ CHAIM in LIKUTEI HALACHOS explains that there are two ways of learning Torah and doing Mitzvos: Lishmah and she'Lo Lishmah. Rava, who says that Torah protects a person from sinning only when he is involved with learning Torah, refers to one who learns she'Lo Lishmah, such as the Torah-learning of Doeg (Sanhedrin 106a). However, when a person learns Torah or does Mitzvos Lishmah, the Torah protects him from the Yetzer ha'Ra even while he is not involved in learning Torah, and Mitzvos protect him from the Yetzer ha'Ra when he is involved in their performance.
The OR HA'CHAIM HA'KADOSH (Vayikra 26:3:7) uses this approach to defend the view of Rav Yosef who suggests that the Torah protects a person from the Yetzer ha'Ra even when he is not learning. The Gemara rejects Rav Yosef's view on the grounds that if the Torah protects a person from sinning, how was it possible that Doeg and Achitofel, who learned Torah, succumbed to sin? The Or ha'Chaim answers that Doeg and Achitofel learned Torah she'Lo Lishmah and that is why their Torah did not protect them while they were not learning. When Rav Yosef explains that Torah protects a person even when he is not learning, he is discussing one who learns Torah Lishmah. (Tosfos may not accept this approach because of this very reason; according to the Chafetz Chaim, Rava's rejection of Rav Yosef's explanation of the Beraisa is not justified. The Chafetz Chaim may understand that a woman who learns Torah is comparable to a man who learns Torah she'Lo Lishmah, since she has no obligation of Talmud Torah. That is why Rava, who is discussing the Torah and Mitzvos of a woman, refer to Torah and Mitzvos she'Lo Lishmah.)
(c) TOSFOS later in the Sugya asks another question. Rav Yosef says that if Achitofel would have realized that the merit of Torah study protects a person from harm, he would not have attempted to harm David ha'Melech. The reason why Achitofel thought he could overpower David ha'Melech was that he suspected that David ha'Melech was involved with the sin of Eshes Ish, and the Torah says that such an act causes the Shechinah to depart from the person and leave him unprotected. Achitofel did not realize that David's Torah-learning would protect him even from such an Aveirah. Tosfos (DH v'Hen) asks that the Gemara earlier says that both Torah and Mitzvos can protect a person from punishment, even while he is not involved in them. Why, then, does Rav Yosef imply that it was the unique merit of Torah that was able to protect David ha'Melech?
To answer these questions, it is necessary to address another question. The Gemara in Berachos (19a) teaches that if one sees a Talmid Chacham transgress an Aveirah at night, he must assume that by the next morning the Talmid Chacham has already repented for his sin. Why, then, did Achitofel assume that he could overpower David ha'Melech, if he knew that David ha'Melech presumably repented for his sin? The answer is that the Mishnah at the end of Yoma (85b) teaches that Teshuvah alone does not suffice to atone for all sins. If a person commits the type of sin that involves Kares or Misas Beis Din, he must first undergo Yisurin (afflictions) in order to gain atonement. If a person commits the type of sin that involves Chilul Hash-m (because the sin is publicized), he does not achieve full atonement until death. Achitofel relied on the fact that David ha'Melech would have to suffer Yisurin and death first in order to gain atonement, and therefore he reasoned that he would be successful in joining Avshalom to vanquish David ha'Melech.
There are two different types of tragedy which may befall a person, Chas v'Shalom. The first type is a tragedy which befalls a person because of natural circumstances (his "Mazal"). The second type is a tragedy one faces as a direct result of his sins ("Yisurin Mechaprin"). When the Beraisa states that Torah and Mitzvos protect a person from evil even when he is not involved in Torah and Mitzvos at the moment, it might refer to natural evils which befall him because of his "Mazal." However, when a person is destined to suffer punishment because of his sins, the Mitzvos he performs cannot protect him from punishment since it has been decreed that he must suffer to atone for his sons. Learning Torah, however, can take the place of physical suffering and even death, because the exertion involved in toiling in Torah is equivalent to physical affliction and even death. (See Tamid 32a, Berachos 63b, Shabbos 88a, and Midrash Tanchuma, beginning of Parshas Noach).
This explains why only Torah was able to protect David ha'Melech. David ha'Melech was deserving of Yisurin to atone for his sins, and only Torah could provide that degree of Yisurin for his atonement.
This also explains Rava's statement. Rava says that the merit of a Mitzvah protects a person permanently, even when he is not involved with the Mitzvah, but it protects him only from natural circumstances. If the person is deserving of punishment and needs Yisurin to atone for his sins, only Torah can provide him with protection. The Beraisa, which compares the Torah to daylight which affords more permanent protection, refers to protection from Yisurin due to Aveiros.
Why does Rava explain that the merit of a Mitzvah can protect a woman from the effects of the Mei Sotah? The Mei Sotah serves to punish her for the sin of adultery, but a Mitzvah cannot protect a person from Yisurin that come for atonement for a sin! The answer is that the punishment that comes from drinking the Mei Sotah is not the same as an ordinary punishment of Misas Beis Din which Beis Din administers in order to punish a wrongdoer and enable him to atone for his sins. Rather, the Mei Sotah proves whether or not she is permitted to her husband by the "natural" element of cause and effect which Hash-m put into the world, wherein a sinner's body reacts to the sanctity of the holy Name mixed with the waters of the Kiyor and the dirt from the floor of the Beis ha'Mikdash. The merit of a Mitzvah is able to protect the woman from this "natural" calamity even though it cannot protect her from the Yisurin which she must suffer eventually due to her sins. (M. Kornfeld)