This passage discusses engaging in Torah study or reciting Shema at bedtime as a remedy against the yetzer hara (evil inclination), stating: 'If the yetzer hara assails you, drag it to the study of Torah.' It connects the bedtime Shema to subduing one's evil inclination before sleep.
אָמַר רַבִּי לֵוִי בַּר חָמָא, אָמַר רַבִּי שִׁמְעוֹן בֶּן לָקִישׁ: לְעוֹלָם יַרְגִּיז אָדָם יֵצֶר טוֹב עַל יֵצֶר הָרַע, שֶׁנֶּאֱמַר: ״רִגְזוּ וְאַל תֶּחֱטָאוּ״ אִם נִצְּחוֹ — מוּטָב, וְאִם לָאו — יַעֲסוֹק בַּתּוֹרָה, שֶׁנֶּאֱמַר: ״אִמְרוּ בִלְבַבְכֶם״. אִם נִצְּחוֹ — מוּטָב, וְאִם לָאו — יִקְרָא קְרִיאַת שְׁמַע, שֶׁנֶּאֱמַר: ״עַל מִשְׁכַּבְכֶם״. אִם נִצְּחוֹ — מוּטָב, וְאִם לָאו — יִזְכּוֹר לוֹ יוֹם הַמִּיתָה, שֶׁנֶּאֱמַר: ״וְדֹמּוּ סֶלָה״. אָמַר רַבִּי יִצְחָק: כׇּל הַקּוֹרֵא קְרִיאַת שְׁמַע עַל מִטָּתוֹ, כְּאִלּוּ אוֹחֵז חֶרֶב שֶׁל שְׁתֵּי פִיּוֹת בְּיָדוֹ. שֶׁנֶּאֱמַר: ״רוֹמְמוֹת אֵל בִּגְרוֹנָם וְחֶרֶב פִּיפִיּוֹת בְּיָדָם״, מַאי מַשְׁמַע? אָמַר מָר זוּטְרָא וְאִיתֵּימָא רַב אָשֵׁי: מֵרֵישָׁא דְעִנְיָנָא, דִּכְתִיב: ״יַעְלְזוּ חֲסִידִים בְּכָבוֹד יְרַנְּנוּ עַל מִשְׁכְּבוֹתָם״. וּכְתִיב בָּתְרֵיהּ: ״רוֹמְמוֹת אֵל בִּגְרוֹנָם וְחֶרֶב פִּיפִיּוֹת בְּיָדָם״. וְאָמַר רַבִּי יִצְחָק: כׇּל הַקּוֹרֵא קְרִיאַת שְׁמַע עַל מִטָּתוֹ — מַזִּיקִין בְּדֵילִין הֵימֶנּוּ. שֶׁנֶּאֱמַר: ״וּבְנֵי רֶשֶׁף יַגְבִּיהוּ עוּף״, וְאֵין ״עוּף״ אֶלָּא תּוֹרָה, שֶׁנֶּאֱמַר: ״הֲתָעִיף עֵינֶיךָ בּוֹ וְאֵינֶנּוּ״. וְאֵין ״רֶשֶׁף״ אֶלָּא מַזִּיקִין, שֶׁנֶּאֱמַר: ״מְזֵי רָעָב וּלְחֻמֵי רֶשֶׁף וְקֶטֶב מְרִירִי״.
Incidental to the verse, “Tremble, and do not sin,” the Gemara mentions that Rabbi Levi bar Ḥama said that Rabbi Shimon ben Lakish said: One should always incite his good inclination against his evil inclination, i.e., that one must constantly struggle so that his evil inclination does not lead him to transgression, as it is stated: "Tremble, and do not sin." If one succeeds and subdues his evil inclination, excellent, but if he does not succeed in subduing it, he should study Torah, as alluded to in the verse: “Say to your heart.” If he subdues his evil inclination, excellent; if not, he should recite Shema, which contains the acceptance of the yoke of God, and the concept of reward and punishment, as it is stated in the verse: “Upon your bed,” which alludes to Shema, where it says: “When you lie down.” If he subdues his evil inclination, excellent; if not, he should remind himself of the day of death, whose silence is alluded to in the continuation of the verse: “And be still, Selah.” The Gemara continues its treatment of the recitation of Shema upon one’s bed. Rabbi Yitzḥak said: Anyone who recites Shema on his bed, it is as if he holds a double-edged sword, guarding him from all evil, as it is stated: “High praises of God in their mouths, and a double-edged sword in their hands” (Psalms 149:6). The Gemara asks: From where is it inferred that this verse from Psalms refers to the recitation of Shema? Mar Zutra, and some say Rav Ashi, said: We derive it from the preceding verse, as it is written: “Let the pious exult in glory; let them joyously sing upon their beds.” The praise of God from one’s bed is the recitation of Shema. And it is written thereafter: “High praises of God in their mouths, and a double-edged sword in their hands.” And Rabbi Yitzḥak said: Anyone who recites Shema upon his bed, demons stay away from him. This is alluded to, as it is stated: “But man is born into trouble, and the sparks [reshef ] fly [uf ] upward” (Job 5:7). The verse is explained: The word fly [uf ] means nothing other than Torah, as Torah is difficult to grasp and easy to lose, like something that floats away, as it is stated: “Will you set your eyes upon it? It is gone; for riches certainly make themselves wings, like an eagle that flies into the heavens” (Proverbs 23:5). The word “sparks” means nothing other than demons, as it is stated: “Wasting of hunger, and the devouring of the sparks [reshef] and bitter destruction [ketev meriri], and the teeth of beasts I will send upon them, with the venom of crawling things of the dust” (Deuteronomy 32:24). Here we see reshef listed along with ketev meriri, both of which are understood by the Sages to be names of demons.