https://www.hebrewbooks.org/pdfpager.aspx?req=60796&st=&pgnum=212&hilite=

(p 190, 212 on PDF)

A. All the mitzvot relate to Atzmus. From Atzmus Himself, we were commanded regarding the matter of mitzvot. This comes from Atzmus Ein Sof, the Master of Will. Therefore, the fact that He is called Atzmus Ein Sof, the Master of Will, is because all of the extensions and revelations—whether prior to the extension and not yet revealed, which is beyond revelation, or afterward, in revelation—all of this is referred to as "Will.”

It is called "Will" because "ratzon" (will) is related to the word "merutzeh" (satisfaction). Therefore, every extension and revelation is referred to as "Will." Furthermore, since it is a revelation of His Will, all extensions and revelations are referred to as "Will." Even the revelations that are beyond Will are also referred to as "Will." This is the meaning behind the gematria (numerical value) of "ratzon"—that while this might not be the level of Will itself, it is still called "Will." Since all extensions and revelations are referred to as "Will," Atzmus of Ein Sof, who is beyond the framework of extension and revelation, is called the "Master of Will."

Thus, regarding mitzvot, we were obligated and commanded directly from Atzmus Himself, which means from Atzmus of Ein Sof, the Master of Will.

B. In truth, we cannot even refer to Him as Ein Sof, because "Ein Sof" is also a description, and Atzmus is beyond any description, as He is beyond extension. Therefore, we cannot call Atzmus Himself by the name Ein Sof either. The reason we still refer to Him as Ein Sof, as explained in the discourses of Rosh Hashanah, is because "Ein Sof" implies the negation of all descriptions, the negation of both the finite and the infinite. For "infinite" (bli gevul) is itself also a limitation, as it is simply the negation of finitude. However, the concept of "without limitation" (bli gevul) refers to the negation of all descriptions, the negation of finitude, the negation of infinity, the negation of affirmation, and the negation of negation.

Thus, from Atzmus of Ein Sof, the Master of Will, we were commanded directly regarding the mitzvot. We know no one else; we know only Atzmus. From Him alone, we were commanded regarding the mitzvot. We do not know Atzmus, and not only do we not know, no one knows—not even Adam Kadmon. For there is no thought that can grasp Him, not even the primordial thought of Adam Kadmon.

We also do not know what we truly are. Although we are human beings, and although we are souls, and although we are human, we can say that we do not know—meaning, we can say that we do not know anything. Adam Kadmon does not know either, and we do not know. For if we knew what Atzmus is, we would be Atzmus, as the sage said (this is a statement of a sage, which is often quoted): "If I knew Him, I would be Him." For through knowing, one becomes connected to the thing, and one becomes unified with it. Therefore, one becomes the thing itself, because through becoming connected and unified with it in complete unity, one becomes the thing.

C. This concept also applies to revelations: through knowing a revelation, one becomes unified with it to the point that they become the revelation. However, the main idea here is with regard to Atzmus. In revelations, one does not experience the full delight of comprehension, meaning one becomes attached to and unified with the revelation, but does not actually become the revelation itself. But with Atzmus, it is different. When one knows Atzmus, they become Atzmus.

In revelations, this does not fully apply. Through knowing revelations, one becomes attached and unified with them, but does not actually become the revelation. In contrast, with Atzmus, knowing Him results in becoming Atzmus. In revelations, through knowing them, one clings to and becomes united with them, but they do not become them.

Let’s put it this way: He knows the matters that necessitate how things must be, yet in practice, they are not necessarily that way. This shows us that even though He knows, this does not mean He becomes what He knows. The knowledge He has pertains to matters that dictate how things should be, but He is entirely different. It's like a Rav who knows the legal ruling (halachic judgment). However, the Rav's knowledge is not limited to just the external aspects of the judgment; he also knows it in a deeper, intellectual way. Through this knowledge, the Rav does not become the matter itself. It could be that the matter could turn out differently, and this is how it works in revelations. However, in Atzmus, the situation is truly different: if one were to know Atzmus, they would become Atzmus.

This first happens due to the purification and refinement of the person. When one reaches such a level that they know Atzmus, they naturally become Atzmus. However, this is not simple at all. The main point is that Atzmus draws the person in because Atzmus created this individual to exist outside of Himself in order for something to be accomplished. Thus, when one reaches knowledge of Atzmus, Atzmus brings the person in. "I made you outside of Myself; now that you come to know Atzmus, I take you in." You know Me; you are Me. You are not yours; you are Mine.

This is the meaning of the statement: "If I knew Him, I would be Him." There are great sages from the later generations who have seen this explained in Kabbalah by pious individuals who have elucidated this idea of "If I knew Him, I would be Him." A being that is not bound by limitations cannot be understood by a finite being. Therefore, if one were to truly understand something unlimited, they would become unlimited themselves. However, this is still not fully comprehensible. How does a finite being become truly unlimited? How does the concept "If I knew Him, I would be Him" work?

As I am explaining, it seems clear that this is because of Atzmus. Atzmus draws the person in—just as the Rebbe Shlita explained—because from the perspective of Atzmus, it is possible for something to be both finite and yet still be connected to Atzmus, which is unlimited.

D. Thus, what Atzmus is—we do not know. Since we do not know what Atzmus is, still, we can have some approximation or sense of Atzmus. We have an approximation of what Atzmus is! One thing we do know is that Atzmus does not receive from anyone. The proof of this is that when nothing else exists, Atzmus still exists. This shows that Atzmus is not dependent on anything or anyone.

Additionally, Atzmus exists in everything, and the proof of this is that the essence (atzmiut) remains even when everything else ceases to exist. Therefore, we, who dwell in physical bodies made of flesh, can perceive something of this essence. Take dust, for example: the fundamental element of dust is below the four basic elements, yet it still retains its essence. Dust is an essence (atzmi), and within it are present both qualities that exist in any true essence.

One quality is that it does not receive from anyone. The proof of this is that if everything that exists were to cease existing, whatever was created would also cease, but Atzmus would remain unchanged. If everything were to cease to exist (God forbid), which we are required to say cannot happen, since we desire that everything should continue to exist, the physical aspect of the world wouldn’t remain, but that’s not what we mean here. The point is that if all things ceased to exist, everything would turn into nothingness. Fire, for example, brings about the ultimate annihilation that can exist in our experience. When the wind blows, it does not bring total destruction, and the same goes for water. Water causes destruction, but not complete annihilation. Fire, however, brings about total destruction.

If everything were to turn into nothingness through fire, only dust would remain. And again, we see that essence is found in everything, because from everything, dust remains. This is similar to how, when wood is burned by fire, dust (ash) remains. That dust is the essence that remains, although it is just a small amount. Similarly, if you take a piece of wood that has been shaped into a form (a figure or sculpture), and then burn that form in fire, the dust will remain. That is the essence of the dust, but this is something that a person shaped into a form.

The same applies to what the Creator has made within this world in the forms of inanimate objects and plants. If they are burned, dust will remain. This shows us that dust (essence) is present in everything.

If everything were to cease to exist (God forbid), which we are required to say cannot happen, since we desire that everything should continue to exist, the physical aspect of the world wouldn’t remain, but that’s not what we mean here. The point is that if all things ceased to exist, everything would turn into nothingness. Fire, for example, brings about the ultimate annihilation that can exist in our experience. When the wind blows, it does not bring total destruction, and the same goes for water. Water causes destruction, but not complete annihilation. Fire, however, brings about total destruction.