Our Gemara on Amud Aleph discusses the protective quality of Torah study and mitzvos:

 ״כִּי נֵר מִצְוָה וְתוֹרָה אוֹר״, תָּלָה הַכָּתוּב אֶת הַמִּצְוָה בְּנֵר, וְאֶת הַתּוֹרָה בְּאוֹר. אֶת הַמִּצְוָה בְּנֵר, לוֹמַר לָךְ: מָה נֵר אֵינָהּ מְגִינָּה אֶלָּא לְפִי שָׁעָה — אַף מִצְוָה אֵינָהּ מְגִינָּה אֶלָּא לְפִי שָׁעָה.

“For the mitzvah is a lamp and the Torah is light” (Proverbs 6:23). The verse associates the mitzvah with a lamp and the Torah with the light of the sun. The mitzva is associated with a lamp in order to say to you: Just as a lamp does not protect one by its light extensively but only temporarily, while the lamp is in one’s hand, so too, a mitzva protects one only temporarily, i.e., while one is performing the mitzva.

וְאֶת הַתּוֹרָה בְּאוֹר, לוֹמַר לָךְ: מָה אוֹר מֵגֵין לָעוֹלָם, אַף תּוֹרָה מְגִינָּה לָעוֹלָם. וְאוֹמֵר: ״בְּהִתְהַלֶּכְךָ תַּנְחֶה אֹתְךָ וְגוֹ׳״. ״בְּהִתְהַלֶּכְךָ תַּנְחֶה אֹתְךָ״ — זֶה הָעוֹלָם הַזֶּה. ״בְּשָׁכְבְּךָ תִּשְׁמוֹר עָלֶיךָ״ — זוֹ מִיתָה. ״וַהֲקִיצוֹתָ הִיא תְשִׂיחֶךָ״ — לֶעָתִיד לָבֹא.

And the Torah is associated with light in order to say to you: Just as the light of the sun protects one forever, so too, the Torah one studies protects one forever; and it states in the previous verse with regard to the Torah: “When you walk, it shall lead you; when you lie down, it shall watch over you; and when you awake, it shall talk with you” (Proverbs 6:22). The Gemara explains: “When you walk, it shall lead you”; this is referring to when one is in this world. “When you lie down, it shall watch over you”; this is referring to the time of death, when one lies in his grave. “And when you awake, it shall talk with you”; this is referring to the time to come after the resurrection of the dead. The Torah that one studies protects and guides him both in this world and in the next world.

מָשָׁל לְאָדָם שֶׁהָיָה מְהַלֵּךְ בְּאִישׁוֹן לַיְלָה וַאֲפֵילָה, וּמִתְיָירֵא מִן הַקּוֹצִים וּמִן הַפְּחָתִים וּמִן הַבַּרְקָנִים, וּמֵחַיָּה רָעָה וּמִן הַלִּסְטִין, וְאֵינוֹ יוֹדֵעַ בְּאֵיזֶה דֶּרֶךְ מְהַלֵּךְ.

This can be illustrated by a parable, as it is comparable to a man who is walking in the blackness of night and the darkness, and he is afraid of the thorns, and of the pits, and of the thistles, which he cannot see due to the darkness. And he is also afraid of the wild animals and of the bandits that lurk at night, and he does not know which way he is walking.

נִזְדַּמְּנָה לוֹ אֲבוּקָה שֶׁל אוּר — נִיצַּל מִן הַקּוֹצִים וּמִן הַפְּחָתִים וּמִן הַבַּרְקָנִים, וַעֲדַיִין מִתְיָירֵא מֵחַיָּה רָעָה וּמִן הַלִּיסְטִין, וְאֵינוֹ יוֹדֵעַ בְּאֵיזֶה דֶּרֶךְ מְהַלֵּךְ. כֵּיוָן שֶׁעָלָה עַמּוּד הַשַּׁחַר — נִיצַּל מֵחַיָּה רָעָה וּמִן הַלִּיסְטִין, וַעֲדַיִין אֵינוֹ יוֹדֵעַ בְּאֵיזֶה דֶּרֶךְ מְהַלֵּךְ. הִגִּיעַ לְפָרָשַׁת דְּרָכִים — נִיצַּל מִכּוּלָּם.

If a torch of fire comes his way, which is analogous to a mitzva, he is safe from the thorns and from the pits and from the thistles, but he is still afraid of the wild animals and of the bandits, and still does not know which way he is walking. Once the light of dawn rises, which is analogous to Torah study, he is safe from the wild animals and from the bandits, which no longer roam the roads, but he still does not know which way he is walking. If he arrives at a crossroads and recognizes the way, he is saved from all of them.

מַאי פָּרָשַׁת דְּרָכִים? אָמַר רַב חִסְדָּא: זֶה תַּלְמִיד חָכָם וְיוֹם מִיתָה. רַב נַחְמָן בַּר יִצְחָק אָמַר: זֶה תַּלְמִיד חָכָם וְיִרְאַת חֵטְא. מָר זוּטְרָא אָמַר: זֶה תַּלְמִיד חָכָם דְּסָלְקָא לֵיהּ שְׁמַעְתָּתָא אַלִּיבָּא דְהִלְכְתָא.

With regard to the aforementioned parable, the Gemara asks: What is the meaning of the crossroads, which provide clarity? Rav Ḥisda says: This is referring to a Torah scholar and his day of death. Due to his continued commitment to the Torah, when the time comes for him to die, it is clear to him that he will go to the place of his eternal reward. Rav Naḥman bar Yitzḥak says: This is a Torah scholar who has also acquired fear of sin, as his fear of sin guides him to the correct understanding of the Torah. Mar Zutra says: This is a Torah scholar who reaches conclusions from his discussion in accordance with the halakha, as that is an indication that he is following the right path.

Let us examine this verse closely as it speaks of an important metaphysical and theological principle, according to the Maharal (Nesivos Olam, Nesiv Hatorah, 1 and 17.) Before we discuss the Maharal, I will point out an important anachronism that can be mistranslated. People often translate Ner as candle, because that is how it is used in modern Hebrew. However, it is not a candle, but it is a lamp. We know this because candles were not invented, or at least not used popularly, until the middle ages. The mechanism of a candle is different than that of a lamp. The candle burns downward on the wick as it continues to consume the fuel, be it wax or paraffin. However, the lamp channels oil up through the wick and somehow it maintains the wick from burning down by the continuous flow of oil through the wick.

Keeping this mechanism in mind, the Maharal explains that Torah itself is something non-physical, and non-earthly, and cannot be contained or channeled directly. This is similar to the flame on top of the wick which you can’t really hold and you can’t sustain it without having the wick and the oil flowing into the wick.  So too, Torah is a spiritual entity and needs the physical performance of mitzvos in order to hold the flame in this world. Yet, just as with the lamp, the main part is the light, so too with Torah and the Mitzvah, the main part is the Torah.  We have this dichotomy, where even though the Torah is the essential element, we cannot preserve Torah without physical action and mitzvos.  This is human nature, we can philosophize all day long but we will not achieve these heights with Torah study alone, we must also do real work in this world.  As Rav Soloveitchik warns in Halakhic Man (p.41): 

There is nothing so physically and spiritually destructive as diverting one’s attention from this world. And, by contrast, how courageous is halakhic man who does not flee from this world, who does not seek to escape to some pure, supernal realm (Halakhic Man, p.41). 

For more on this see Iggeres HaGrah (8), Nefesh HaChayyim (4:29).

The Maharal continues to explain that since the Torah is spiritual and exists beyond time it is compared by the Gemara to daylight because it is a permanent light and not transient, unlike the lamp at night, which only provides temporary safety. Furthermore, when the Gemara refers to the Crossroads, the day of death, it is referring to the clarity that comes from depth of Torah study. Meaning to say, a particular mitzvah that is performed provides a certain amount of light and protection, but it does not represent permanent enlightenment, and therefore only protects at the time that one is involved in it, as the lamp only provides a light at night so long as it is lit. But the clarity that comes from achieving a higher spiritual plane, that is the “crossroads“ or time of death, allows for a permanent state of elevation and awareness of the truth. Finally, the best part is that the Torah sage who is able to come to the truth of torah through his deep analysis, will be able to achieve this high level of protection in this world, because he is transcending it through the enlightenment of his Torah study. This is represented by the Torah scholar whose conclusions are in accordance with the halakha.