The ה'—the letter Hei—being discussed here is actually the lower Hei, the final Hei of the Shem Havayah. The Alter Rebbe is clarifying that even though we are talking about the creation of this world, which is associated with the lower Hei, there is a connection to the higher Hei as well.

He points out that when we say the world was created with the Hei, we are referring specifically to the ה' תתאה—the lower Hei, the last letter of the Shem Havayah. This is the Hei that comes after the Vav, representing the level of Malchus, the attribute of sovereignty that brings creation into being.

Our sages, Chazal, expounded on this idea by referencing the verse כי ב"יה ה' צור עולמים—'For with Yud and Hei, Hashem formed the worlds.' They interpreted this verse as referring to the two Hei's in the Shem Havayah, each representing a different aspect of creation.

However, the Gemara actually applies this verse to the first Hei—the higher Hei of the Shem Havayah. This seems to create a contradiction, since here we are discussing the lower Hei in relation to the creation of this world.

The Alter Rebbe resolves this by explaining that the lower Hei is rooted in and receives its influence from the higher Hei. The process of revelation begins with the Yud, which is hidden and represents the point of wisdom. For that wisdom to be revealed, it must pass through the higher Hei, which is the level of Bina—understanding.

So, the source and beginning of the lower Hei's revelation is actually drawn from the higher Hei. The flow starts with the Yud, then is revealed through the higher Hei, and only then does it extend to the lower Hei, which is associated with Malchus and the actual creation of this world.

The Hei is written with both length and width, which alludes to the concept of התפשטות—expansion. This expansion is a symbol of Bina, the faculty of understanding.

In other words, the hidden wisdom of the Yud becomes expanded and revealed in the Hei, which is the process of בינה—the intellect being broadened and comprehended in a way that can be grasped and understood in detail.

The influence of Bina—this expansion and revelation—ultimately concludes in the heart. The process is that the intellect, after being expanded and understood, affects the emotions, which are centered in the heart.

This means that the intellectual understanding of Bina is not just theoretical; it leads to emotional response and feeling, which is the next stage in the chain of spiritual flow.

This is as it is written in the Tikkunei Zohar: דבינה לבא ובה הלב מבין—'Bina is the heart, and with it the heart understands.' This phrase emphasizes that the heart's understanding and feeling are rooted in the faculty of Bina.

Through Bina, the intellect is internalized and becomes an emotional experience, affecting the heart and the person's inner life.

From this emotional state in the heart, there emerges the הבל—the breath or vapor—which is the source for the revelation of the physical letters of speech. These letters are articulated through the five organs of speech, known as the ה' מוצאות.

This process begins with the hidden point of the Yud, passes through Bina and the heart, and finally emerges as the breath that forms the actual spoken letters. The materialization of speech is thus rooted in the entire chain of spiritual faculties.

The form of the lower Hei when written—with its length and width—also hints at the expansion of מלכותו יתברך—His blessed sovereignty. This is the attribute of Malchus, the sovereignty of all worlds, which extends above, below, and in all four directions.

This expansion and extension come from the letters of the דבר ה'—the word of Hashem. The Hei, with its open and expansive shape, represents how Hashem's kingship and creative power spread out to encompass all of existence, bringing everything into being through His speech.

The Alter Rebbe brings a verse from Koheles: באשר דבר מלך שלטון—"For the word of the king is rule." This phrase is used to illustrate the idea that the speech of the king itself is what establishes authority and dominion. In the context of the discussion, this is a reference to how Malchus—the attribute of kingship—expresses itself through dibur, speech.

The Alter Rebbe is emphasizing that just as in a human king, his power and rule are manifest through his words and decrees, so too, in the spiritual sense, Malchus—the Divine attribute of sovereignty—finds its expression and actualization through the letters of speech. This is the source from which all creation and existence emanate, as everything is brought into being through the dibur—the speech—of Hashem.

He notes that this is explained further elsewhere (כמ"ש במ"א), indicating that this concept is elaborated in other places in Chassidus, where the connection between Malchus, speech, and the creation of worlds is discussed in depth.

Now, the Alter Rebbe introduces a new point: to understand, even if only a little, the nature and essence of the letters of speech in G‑dliness—אותיות הדבור באלהות. He points out that when we speak about Hashem, we must be very careful not to attribute any physical form or even a soul-like quality to Him, G‑d forbid. שאין לו דמות הגוף ולא הנפש ח"ו—He has neither the form of a body nor of a soul, Heaven forbid.

This is an important clarification, because up until now, the discussion has been using the analogy of human speech and the process by which letters and words are formed in the heart and then expressed. But when it comes to Hashem, we cannot take these analogies literally. The letters of speech as they exist in G‑dliness are not physical, nor are they even spiritual in the way we understand a soul. They are completely beyond our grasp and have no comparison to anything in our experience.

The Alter Rebbe is preparing us to approach this subject with humility and caution, recognizing that all our descriptions are only metaphors to help us understand, but they do not capture the true essence of how things are in G‑dliness.

The Alter Rebbe reminds us that this topic—the nature of the Divine letters of speech—has already been explained at length elsewhere. He says, כבר נתבאר בדרך ארוכה וקצרה—it has already been explained both in a long and a short way.

This means that in other places in Chassidus, the Alter Rebbe has gone into detail about how the concept of Divine speech works, and how it is completely different from human speech. There are both extended explanations and more concise ones available for those who want to study the subject further.

Here, the Alter Rebbe refers us to specific chapters in another work: (בלק"א ח"ב פי"א וי"ב ע"ש)—see Likkutei Amarim, part two, chapters 11 and 12. He is directing the reader to look there for a more thorough treatment of the subject.

In other words, if you want to understand this idea in greater depth—the nature of the Divine letters of speech and how they relate to creation—you should study those chapters, where the Alter Rebbe discusses it in detail.