Understanding the enneagram in the context of Ibn al 'Arabi's teachings involves mastering a fairly complex set of hierarchical concepts, but I will try to simplify it as much as possible.
Al 'Arabi proposes two congruent entities that constitute what we would call "God." One of them, the Essence, is unknowable and will always remain so; one could definitely draw some parallels between this entity and Gurdjieff's discussions on essence (notably found in his book Views From The Real World) simply because essence, in man, performs a similar role, which would be beyond the scope of this essay to explain. In this case, however, what we see is an unknowable, Essence, and then what al 'Arabi refers to as Divinity, that is, God within the context of material manifestation.
Essence is absolutely unknowable. In the Futuhât al-makkiyya, al 'Arabi states:
"... The Essence of the Real is outside this judgment, for it is witnessed before it is known. Or, rather, it is witnessed, but not known, just as the Divinity is known, but not witnessed." He also says, " we have no knowledge of God except through attributes of incomparability or attributes of acts. He who supposes that he has knowledge of positive attributes of the Self has supposed wrongly. For such an attribute would define Him, but His Essence has no definition. This is a door locked to engendered existence, a door that cannot be opened."
(The Sufi path of knowledge, Wliiam Chittick, State University of New York press, 1989, pgs. 58 & 60.)
God can, however, be "known" through his names in this context, although each one is a mere shadow of the unknowable Essence. Because a man will never be able to know God in his Essence (as explained in al 'Arabi's Futuhât al-makkiyya), the best he can do is make an effort to know God through Divinity, via the names, and, indeed, the hierarchy of names and a man's understanding of them determine his place.
Divinity refers to level, whereas Essence refers to entity. Divinity presumes relationship to creatures, whereas Essence exists as a reality itself, without any relationships (ibid, p. 59.)
The names represent characteristics of God, which convey essential relationships. As Chittick explains,
"The Divine presence includes the Essence, the Attributes, and the Acts. The Attributes are names are the barzakh (isthmus) between the Essence and the Acts. But these names can be divided into two categories, depending on the type of relationship which they designate between the Essence in the cosmos. In the first case, they negate various qualities from the Essence. In the second, they affirm that the Essence in as much as it is a God, and possesses various qualities."
(ibid, p. 58.)
This may be confusing to the general reader, so allow me to explain that in this case the word "Attributes," or names, does not represent things, but rather, qualities that God has, (also, forces) and the word "Acts" represents all of the material creations that God has made manifest.
Acts, in other words, represent things; and names represent actions on those things. Rendered crudely, "Essence, Acts, and Attributes" can be interpreted as "God, things, and stuff that exerts forces on things." An oversimplification, to be sure, but you get the general idea.
In the diagram, the Names or Attributes of the Essence are represented by the notes, each one of which represents a particular quality of God that can be manifest through a material act (thing). We can understand the hierarchy, or elevation (evolution) of energy as departing from God (right side of the diagram, in which the initial manifestation of material reality creates a division between God and his creation) and returning to God (left side of the diagram, the evolution of energy back towards the essence.) Lest readers doubt that the names have a specific ranking, this excerpt from the Futuhât al-makkiyya will set the record straight.
The attributes which negate qualities from the Essence are all related to qualities of God that contact the material world and its consequences, representing, in the general sense, a lower level of intelligence both of origin and self. Conscious labor is needed to reconcile these forces before any return to the absolute can be attempted.
Inevitably, once we reached the attributes that affirm qualities from the Essence, the work must involve surrendering, or suffering, since everything "acquired" during the active process of negation must be given up. This work is clearly progressive; and it ultimately affirms the incomparability of God, that is, the Essence, because the process which has consisted of one comparison after another in its evolution from the material, up through desire, power, being, purification, and wisdom — ultimately has to surrender this action to return to its source.
Ah, you may well say, if you have followed me so far. You've explained the attributes and how they are notes; but where are the acts? And this is a bit of a trick question, because they are here; hidden in plain sight.
Any single octave as a whole represents an Act. In what may seem paradoxical, but is in fact quite logical, every "thing" or Act represents a whole octave in and of itself, dependent on octaves above and below it, of course, as is necessary in the hierarchy. Yet each octave contains all of the names of God, or attributes, in it, in one form or another, and all the principal Attributes (forces) contribute to the action of the Attributes upon the Act, or thing. This means that all things contain, in a microcosmic sense, a complete expression of God with all of the Attributes, or names, extant in potential. Everything, in other words, contains all forces. It is the degree to which each of those forces express themselves, and the harmonious relationship of the expression of forces between one another, that determines the completion of the octave and the level on which it vibrates.
Although a man, in other words, has all the names of God in him, some forces always can and will predominate over others.
Al 'Arabi presents a brilliant summary of the potential contradictions we encounter in trying to understand why some of the names of God appear to produce horrific results in the real world; the subject is far too detailed to treat here, but a good recap of it can be found in pages 47 through 58 of "The Sufi Path of Knowledge," in the chapter entitled "The Divine Roots of Hierarchy and Conflict."
In regard to the question of incomparability of Essence, it's notable that Gurdjieff's seemingly peculiar chosen names for God and his place of residence (Uni-Being endlessness, Most Holy Sun Absolute, etc.) adopt the traditional language used in Sufi expressions of incomparability, indicating a plausible source for his understanding of how such things were to be expressed.