On the mizbeiach all night until the morning—in the merit of the Torah that burns during the night, that is studied during the night, a person is safeguarded from the “chitzonim” while he is asleep until the morning. Thus, the passuk assures that it portends the following: “And the fire of the mizbeiach shall be kept aflame on it”—even during one’s sleep, the fire of the Torah will burn within him warding off the “chitzonim,” preventing them from exerting their negative influence over him.
This explains magnificently the continuation of the text: "אש תמיד תוקד על המזבח לא תכבה"—a fire shall remain aflame continually on the mizbeiach; you shall not extinguish it. According to the Zohar hakadosh (Tzav 28b), this passuk alludes to the Torah that is compared to fire. It is not extinguished, because even an aveirah does not extinguish the fire of the Torah. And the mitzvos of the Torah performed by the Rabbis is Torah within them that is not extinguished day or night, because they uphold the dictum: “You should contemplate it day and night.” And the smoke that ascends from their mouths with words of Torah is the fire of the array (on the mizbeiach).
Now, this illuminates for us the profound message of Rabbi Shimon bar Yochai in relation to the words: “Command Aharon and his sons.” He explains that there is a greater need for Scripture to urge in a situation involving the loss of money. In keeping with our current discussion, we can suggest that he is alluding to the need to study Torah at night, so that we will be afforded protection while asleep, when a person’s neshamah and the Torah he learned that day leave him.
This then is what he means by a “loss of money”—“chisaron keese” (literally: an empty pocket). He is hinting to us a fascinating concept. The human body resembles a pocket that holds a Jew’s pure neshamah and all of his Torah inside it. Accordingly, during the day, when he is studying Torah and performing mitzvos, the body does not resemble an “empty pocket.” It is filled with the brilliant light of the Torah! As David HaMelech expresses it (Tehillim 40, 9): "לעשות רצונך אלקי חפצתי ותורתך בתוך מעי"—to fulfill Your will, my G-d, do I desire, and your Torah is in my internal organs.
The situation changes, however, at night. Since the neshamah along with the Torah the Jew learned that day and the mitzvos he performed vanish, his body can be compared to an “empty pocket.” As such, he is not protected by his Torah and mitzvos; the “chitzonim” view this as an opportunity to invade and prevail over him. Therefore, the Torah issues a stern, urgent warning—a remedy to avoid this undesirable situation: "זאת תורת העולה היא העולה על מוקדה כל הלילה עד הבוקר". A Jew should study Torah at the beginning of the night, so that the fire of the Torah will continue to burn within him and protect him throughout the night until HKB”H returns his neshamah to him in the morning.
To reinforce this warning, the Torah adds: "אש תמיד תוקד על המזבח לא תכבה"—this fire must be constant; it must burn both during the day and during the night; it should never be extinguished!
