The study of halacha has a special virtue.

  The Tanya says many good things here. The study of halacha has a special virtue. The study of esoteric material is its own value. See depends how you look at it. Then you must fulfill all the mitzvos. All of this is a rebuke to the yeshiva world which values none of it and never talks hashkafa in such an intelligent way. 

אבל דוקא סודות המצוה

This, however, refers only to [the study of] the Kabbalistic mysteries of the mitzvah itself,

דלא גרע מלימוד הלכותיה, ואדרבה כו׳

for this is not inferior to the study of its laws; indeed, quite the contrary...,

אף שאינו משיג המהות

even though he does not apprehend the essence of the spiritual intent of the mitzvah as it applies to the visages of Atzilut.

Moreover, his understanding of the essence of the etrog, the object with which the mitzvah is observed, grants him some comprehension of the essence of the mystical reaches of the subject at large.

מה שאין כן בסדר ההשתלשלות

It does not apply to [the study of] the order of Hishtalshelut, the chainlike stages of progressive self-screening whereby the Divine light descends from level to level until ultimately this corporeal world is created:

אף אם משיג המציאות

Even if one does comprehend the external aspect of the existence of the Sefirot and spiritual levels involved,

לא עדיף מצד עצמו כלימוד המצות, שמשיג ותופס המהות

this is not intrinsically as worthy as the study of the laws of the mitzvot, where one comprehends and grasps their essence.

Knowledge of the various spiritual levels may indeed be superior for an unrelated reason, namely, that it leads to a “complete heart” (lev shalem), a wholehearted awe of G‑d — and this, as the Alter Rebbe will later say, is the purpose of all the mitzvot. Intrinsically, however, gaining this knowledge is not superior to studying the laws governing the performance of the mitzvot, whose essence he can understand.

ומעלה עליו כאילו קיים בפועל ממש

Moreover, this [study] is considered [in certain cases] the equivalent of actual performance,

כמו שכתוב: זאת התורה כו׳

as it is written,1 “This is the law [of the burnt offering and the meal offering...].”

The Gemara comments on this,2 “He who occupies himself with these laws is considered as if he had actually offered a burnt offering and a meal offering.”

Mastering the revealed laws of the commandments is thus in one sense superior to delving into the innermost dimension (the pnimiyut) of the Torah, on esoteric subjects such as the order of Hishtalshelut. For the study of the laws relates to the essence of the subject at hand, such as the physical objects with which the commandments are performed.

G‑d’s wisdom, moreover, which is inherent in these laws, descends and permeates the physical objects around which the laws revolve. It is thus the essence of G‑d’s wisdom that the student comprehends, and thereby he becomes involved in the “wondrous union” described in ch. 5 of Tanya, whereby his mortal intellect simultaneously “encompasses and is encompassed by” the Divine wisdom embodied in the Torah which he is studying. This intellectual union in turn unites his soul (which transcends his intellect) with the infinite light that is vested in the wisdom of the Torah.

The above is true only when he understands the essence of his subject. This is the case when he studies (for example) the laws regulating the observance of the commandments. If, by contrast, his subject is the hierarchies of angels in the Worlds of Beriah, Yetzirah and Asiyah, or, yet higher, the configurations of Sefirot within the World of Atzilut, then his grasp is no more than external: he may indeed be aware of his subject’s existence, but he will be unable to know its essence.

* * *

And now, all the above notwithstanding, the Alter Rebbe is about to point out the superior aspect of the study of Hishtalshelut.

אלא שידיעת המציאות מההשתלשלות היא גם כן מצוה רמה ונשאה, ואדרבה, עולה על כולנה

However, the knowledge of the existence of the Hishtalshelut is also a lofty and exalted mitzvah.3 Indeed, it outweighs them all, all of the mitzvot and the study of the laws of the Torah.

כמו שכתוב: וידעת היום כו׳

Thus it is written,4 “Know this day [...that the L‑rd is G‑d],”

דע את אלקי אביך כו׳

and5 “Know the G‑d of your father...”; i.e., there is an obligation to attain a knowledge or apprehension of Divinity.

ומביאה ללב שלם כו׳

Moreover, this leads to a “whole heart,” for the latter verse concludes, “and serve Him with a whole heart”; i.e., a knowledge of G‑d leads one to serve Him with one’s entire being.

As explained in Likkutei Torah, in the discourse beginning VeLo Tashbit, this refers to serving G‑d with awe — and this is the ultimate intent of all the mitzvot, as the Torah states,6 “G‑d has commanded us to perform all these statutes so that we may fear the L‑rd our G‑d.” And it is the study of the innermost dimensions of the Torah and a knowledge of the various spiritual levels which comprise the order of Hishtalshelut that enable one to fulfill the mitzvah of “knowing G‑d,” which leads in turn to the “whole heart” of “fearing Him.” Thus the Alter Rebbe concludes:

שהוא העיקר

And this is the essential thing: the wholehearted awe of G‑d is the ultimate purpose of all the commandments.

As mentioned above, one can attain this state only through a knowledge of the order of Hishtalshelut, even though this knowledge is merely an awareness of its existence and not a grasp of its essence.

והשגת המציאות הוא להפשיט מגשמיות כו׳

The comprehension of existence entails divesting [this subject] of any physicality....

In other words, one should endeavor to picture its spirituality. Hence, as the Rebbe has often stressed, one should study the innermost and mystical dimension of the Torah in such a way that one7 “derives sustenance from it” (יתפרנסון מיניה) — viz., the “sustenance” derived from comprehension. And soundly-based comprehension can be secured only when this dimension of the Torah is studied with the intellectual elucidation afforded by the teachings of Chabad.

רק שזו היא מצוה אחת מתרי״ג

However, this mitzvah (of knowing G‑d and apprehending Divinity) is but one mitzvah of the 613,

והאדם צריך לקיים כל תרי״ג

and a man must fulfill all 613,

לפי שהן השתלשלות המהות דחיצוניות דכלים דאצילות

for they descend from the essence of the external aspect of the vessels of Atzilut, a source whose standing was explained above.

לכך צריך להרבות בלימוד כל התרי״ג, וקיומן בפועל ממש, במחשבה דבור ומעשה, שהן בריאה, יצירה, עשיה

Hence, one must extensively study all 613 mitzvot, and [hence] fulfill them in actual practice in thought, speech and deed — which parallel Beriah, Yetzirah and Asiyah respectively —

לברר בירורין אשר שם

in order to purify whatever needs purification (beirur) there.

As previously explained, the extraction and elevation of the sparks exiled in the various worlds is the ultimate purpose of creation.