What were see in this Discourse is the preface of an initiation ceremony; a gnostic sage is speaking to his student right before his ascension into a higher realm of enlightenment. In antiquity, the seven planets were known as the seven spheres while the eighth was thought to be where the fixed stars resided. It was also a pivotal, transformative place. The ninth sphere was literally 'god's realm' and what all gnostics reach for when learning, praying, and considering the nature of life itself. In regard to these 'spheres'-- think of an onion.
Hermes Trismegistos is the teacher and the student is unknown. The student could be anyone. The student could be you. (Note: I have an article about Hermes Trismegistos coming up next.)
I find this text, as well as the rest of the Hermetic Literature, to be especially instructive when contemplating lay gnosis(search 'lay gnosis' in the search engine in the blog). Lay gnosis is a physical manifestation of a spiritual transition, and I think it is the eighth realm touched upon by Hermes. This is one of the most esoteric works of his which has survived.
It is lamentable that more Hermetic Literature has not survived the centuries because supposedly there are hundreds of texts which are hidden or were destroyed. Here is what is translated as of today. The complete Hermeticum is available now as well as verified fragments. It's really no wonder that Cosimo de Medici was neck deep in the collection and restoration of the texts, they're such a unique spiritual work. If not for Cosimo then more likely than not the small dialogues in the Nag Hammadi codices would be all we would be left with.
Discourse on the Eighth and Ninth
(The Ogdoad and the Ennead)
"My father, yesterday you promised you would take my mind to the eighth heavenly sphere and after that you would take me to the ninth. You said this is the sequence of the tradition."
"Yes, my child, this is the sequence, but the promise was made about human nature. I said to you when I first made the promise, 'If you remember each of the stages.' After I received the spirit through the power, I established that action for you. Clearly understanding dwells within you. In me it is as if the power were pregnant, for when I conceived from the spring that flows to me, I gave birth."
"Father, you have spoken every word rightly to me, but I am amazed at what you said. You said, 'The power is in me.'"
He said, "I gave birth to it as children are born."
"Then father, I have many siblings if I am to be counted among the generations."
"Right, child. This good thing is counted... always. So, child, you must know your siblings and honor them rightly, since they have come from the same father. For each of the generations have I addressed. I have named them, since they are offspring like these children."
"Then, father, do they have a day?"
"Child, they are spiritual, for they exist as forces that nurture other souls. That is why I say they are immortal."
"Your word is true. From now on it cannot be refuted. Father, begin the discourse on the eighth and ninth, and count me also with my siblings."
"Let us pray, child, to the father of the universe, with your siblings, who are my children, that the father may grant the spirit of eloquence."
"How do they pray, father, when they are united with the generations? Father, I want to obey."
"... It is right for you to remember the progress you have experienced as wisdom in the books. Child, recall your early childhood. You have posed, as children do, senseless and foolish questions."
"Father I have experienced progress and foreknowledge from the books, and they are greater than what is lacking- these matters are my first concern."
"Child, when you understand the truth of your statement, you will find your siblings, who are my children, praying with you."
"Father, I understand nothing else than the beauty I have experienced in the books."
"This is what you call the beauty of the soul- the edification you have experienced in stages. May the understanding come to you, and you will teach."
"I have understood, father, each of the books, and especially...."
"Child... in praises from those who raise them."
"Father, I shall receive from you the power of the discourse you will utter. As it was spoken to the two of us, let us pray, father."
"Child, it is fitting for us to pray to god with all our mind and all our heart and our soul, to ask god that the gift of the eighth reaches us and that each receive from god what belongs to god. Your job is to understand, mine is to be able to utter the discourse from the spring that flows to me."