The central point of the above discussion was that through the occurence of evil thoughts in one’s mind, and through one’s battle against them, the sitra achra is subdued, causing great pleasure above.
The Alter Rebbe now goes on to say that this subjugation of the sitra achra and the consequent Divine pleasure are brought about not only by one’s struggle against the sitra achra when it attempts to lead one to sin (as in our case, where the lack of a struggle against evil thoughts, and the continued meditation on them would constitute a sin). Rather, one produces the same effect by struggling with one’s nature in abstaining from permitted matters. For as explained in ch. 6, any permitted action done without the specific intention of leading one to the serving of G‑d (as, for example, eating in order to obtain strength for Torah study or performing the mitzvot) derives its vitality from the sitra achra. (This term simply means “the other side,” i.e., the absence of holiness.) Only an action so directed can draw its vitality from the realm of holiness. Therefore, whenever one refrains from doing even a permissible act (in which this intention is lacking) in order to subdue the sitra achra, he gives rise to Divine pleasure.
ולא עוד, אלא אפילו בדברים המותרים לגמרי
Furthermore, not only by fighting his evil thoughts does one subdue the sitra achra, but even in matters that are fully permissible,
כל מה שהאדם זובח יצרו אפילו שעה קלה, ומתכוין לאכפיא לסטרא אחרא שבחלל השמאלי
every act of sacrificing one’s impulse, even if only for a short while i.e., if he delays partaking of even the permissible and essential, with the intention of subduing the sitra achra in the left part of his heart, achieves this end.
כגון שחפץ לאכול, ומאחר סעודתו עד לאחר שעה או פחות
For example: when he wants to eat but delays his meal for an hour or less,
ועוסק בתורה באותה שעה
and during that time he studies Torah.
For if he occupies himself with other physical matters, he does not subdue the sitra achra by postponing his meal, since he is in any case indulging his animal soul; but if he studies Torah during that time then even when the delay of his meal does not gain him any time for Torah study, for he would have studied Torah regardless (as will soon be stated), and despite the fact that he eventually does eat, yet he subdues the sitra achra by the mere effort of postponing his meal, and thereby he brings about the Divine pleasure caused by every subjugation of the sitra achra.
כדאיתא בגמרא: שעה רביעית מאכל כל אדם, שעה ששית מאכל תלמידי חכמים
As the Gemara states: “The fourth hour [of the day] is when all men eat, but the sixth hour is the mealtime for scholars,”
והיו מרעיבים עצמם שתי שעות לכוונה זו
because they would go hungry for two hours with this intention,
אף שגם אחר הסעודה היו לומדים כל היום
although even after the meal they would study all day.
וכן אם בולם פיו מלדבר דברים שלבו מתאוה מאד לדברם מענייני העולם
So too if one restrains his mouth from saying things which he greatly desires to say, concerning mundane matters — even where is nothing wrong with the words per se, yet he refrains from speaking them precisely because he feels a desire to do so;
וכן בהרהורי מחשבתו
and likewise regarding the thoughts of his mind he suppresses an urge to think about some mundane matter.
אפילו במעט מזעיר דאתכפיא סטרא אחרא לתתא
Even by the slightest subjugation of the sitra achra here below,
אסתלק יקרא דקודשא בריך הוא וקדושתו לעילא הרבה
the glory of G‑d and His holiness is greatly elevated on high.
ומקדושה זו נמשכת קדושה עליונה על האדם למטה לסייעו סיוע רב ועצום לעבודתו יתברך
From this holiness, a sublime holiness issues forth upon man below, to assist him with a great and powerful aid in his service of G‑d.
וזהו שאמרו רז״ל: אדם מקדש עצמו מעט למטה, מקדשין אותו הרבה מלמעלה
This is what our Sages meant when they said: “If a man consecrates himself in a small measure here below, he is sanctified greatly from above.”
לבד מה שמקיים מצות עשה של תורה: והתקדשתם וכו׳, כשמקדש עצמו במותר לו
This is apart from the fact that when one sanctifies himself in permissible matters, he thereby fulfills the positive commandment of the Torah: “Sanctify yourselves, and be holy.”
Hence, apart from the consolation previously offered the Beinoni — that through “turning away from evil” by combating evil thoughts and desires, he affords G‑d a pleasure that tzaddikim cannot — his battle with the sitra achra also contains a positive quality in the category of “doing good,” that is likewise not present in the divine service of tzaddikim. This positive quality is the fulfillment of the mitzvah: “Sanctify yourselves…,” which applies only to Beinonim, not to tzaddikim. For the intention of the commandment is that even one’s personal, permissible, and mundane matters should not be attended to out of the desire of one’s animal soul, but for the sake of G‑d. This directive cannot apply to tzaddikim, who are unencumbered by desires of the animal soul, as the Alter Rebbe continues:
ופירוש והתקדשתם: שתעשו עצמכם קדושים
The meaning of “Sanctify yourselves” is: “You shall make yourselves holy.”
כלומר: אף שבאמת אינו קדוש ומובדל מסטרא אחרא
That is to say, although in truth one is not holy and separated from the sitra achra,
כי היא בתקפה ובגבורתה כתולדתה בחלל השמאלי
for the sitra achra of his animal soul is still, as at birth, at its full strength and might, in the left part of his heart — the seat of the animal soul and evil inclination,
The word kedushah (“holiness”) means “setting apart,” i.e., separation from the unholy. The verse thus means: One should sanctify himself even if he must yet make himself holy and separate from the sitra achra, for at his present level his heart still desires those things that derive from it,
רק שכובש יצרו ומקדש עצמו
yet if even while at this level he subdues and masters his evil impulse and makes himself “holy”, separate from the sitra achra, then, continues the verse:
“You will be holy.”
The words “be holy” which, in their simple sense, voice a command, can also be understood as conveying a promise,
כלומר: סופו להיות קדוש ומובדל באמת מהסטרא אחרא
meaning that ultimately he will be truly “holy” and removed from the sitra achra,
על ידי שמקדשים אותו הרבה מלמעלה
through his being “greatly sanctified from above,” as quoted earlier from the Gemara,
ומסייעים אותו לגרשה מלבו, מעט מעט
and through his being aided from above to expel [the sitra achra] from his heart, little by little, so that even in his heart he will no longer have any desire for anything originating in the realm of the sitra achra.