Normally, the bulk of my research into classical Hermeticism consists of diving into the footnotes helpfully provided by Brian Copenhaver, M. David Litwa, Clement Salaman, Jean-Pierre Mahé, Hans Dieter Betz, and the like in their various translations of their books and topics.  This generally leads me back to various other books, academics, and the like, generally in the form of papers that have been published at some point in the past three decades (a lot has changed—for the better!—in modern scholarship on Hermeticism), and to various extents, I get quite a fair bit out of it, especially from scholars like Wouter Hanegraaf or Christian Bull.  On occasion, though, I get to something rather niche but rather well-built that falls outside of this, sometimes involving purchases on AbeBooks or even more obscure third-party sellers due to stuff I honestly can’t track down elsewhere.  Not that far back, I had the pleasure of doing just that for a particular monograph by William C. Grece, Corpus Hermeticum XIII and Early Christian Literature (Brill, 1979).

Grese’s monograph (a revised version of his Ph.D. dissertation) not a particularly weighty tome, but it is one I found particularly enjoyable.  Rather than trying at some expansive view of Hermeticism as a whole, Grese’s book focuses on the text of Book XIII of the Corpus Hermeticum (or CH XIII, itself entitled “A secret dialogue of Hermēs Trismegistos on the mountain to his son Tat: on being born again, and on the promise to be silent”). CH XIII is one of the “big three texts”, as I consider it, when it comes to the notion of spiritual ascent and salvation, along with CH I and Discourse on the Eighth and Ninth (from the Nag Hammadi Codices, specifically NHC VI.6, which I also abbreviate as D89).  To be sure, much of the “philosophical/theoretical” Hermetic literature that exists from the classical period talks about matters of theology, theosophy, divinity, and the like, and many others do at least lip service or give a nod to the notion of divine ascent and unification with the Divine, but it’s really these three texts that really get into the nitty-gritty of what that looks or sounds like as an actual ritual or cultic practice—although not all in exactly the same way.  In addition, it’s these three texts (but CH I and CH XIII more than D89) that get into notions of vices and virtues, which has been an exceptionally fruitful for hashing out notions of Hermetic morality or even prayers:

1. (July 2019) The Twelve Irrational Tormentors and the Ten (or Seven) Rational Powers
2. (March 2020) On Hermetic Tormentors and Egyptian Sins
3. (August 2020) Twelve, Ten, and Seven: Clarifying and Rethinking the Tormentors from CH XIII
4. (November 2021) The Hermetic Refranations and Repentances

And, when it comes to prayers, CH XIII is the source for us of the ὑμνῳδία κρύπτη, the “secret hymnody”, one of the few extant prayers given to us in the classical Hermetic texts (right up there with the Triple Trisagion from CH I or the Prayer of Thanksgiving from the end of the Perfect Sermon, NHC VI.7, or PGM III).  It’s a fascinating text—although problematic at times in understanding how it posits a relationship between us where we are and Divinity as it is and how we get from one point to the other—and Grese’s book is an in-depth, profoundly detailed approach to understanding every line and word in the text.

To be fair, as evident from the title, that isn’t Grese’s only aim.  As he says in his introduction:

The parallels between C.H. XIII and the NT [New Testament] to which Lagrange points really only show that C.H. XIII and ECL [Early Christian Literature] both made use of similar religious language and that both were part of the same world of Hellenistic religions.  Thus the study of the language and message of C.H. XIII should help us understand the religious context of ECL and also ECL itself.

This study then is an attempt to use C.H. XIII to increase our understanding of ECL…

But, as he notes in his conclusion:

When Richard Reitzenstein published Poimandres in 1904, one of his explicit intentions was to awaken NT scholars to the religions of the Hellenistic world and to the importance that they hold for understanding the NT.  Reitzenstein chose the Hermetica for this purpose because he considered them to be one of the best surviving examples of Hellenistic religion.  The parallels between the Hermetic and ECL thus became a way to study the influence of the Hellenistic world on primitive Christianity.

It has not been my intention to prove again Reitzenstein’s thesis.  Instead, by collecting the many parallels between ECL and C.H. XIII in order to make them more accessible to students of ECL I have continued the work Reitzenstein began.  There have been some, as we noted, who argued against Reitzenstein that this or that parallel was the result of the NT influencing C.H. XIII, but nowhere in our analysis did we find any evidence that would support such a claim.

Even if Grese intended to use CH XIII to help understand the world of early Christian literature, he has certainly done the work in also understanding CH XIII itself on its own terms, especially in light of other classical Hermetic texts both from the CH and elsewhere.  Besides, let’s be honest, even if we don’t take the claims of C.H. Dodd from his The Bible and the Greeks as seriously as he himself does, even if we don’t necessarily take tight parallels between Hermetic and Roman Empire-period Jewish or Christian stuff as being evidence of influence, Grese makes the great point that Hermeticism and various other religious movements at the time participated in this overall Hellenistic (not the same thing as Hellenic) framework of religion, faith, spirituality, and ritual practice.

The bulk of the Grese’s book is given to a thorough, line-by-line (even word-by-word) breakdown and analysis of the content of CH XIII, and pointing out parallels with various bits of Christian scripture and gospel as might be appropriate.  It’s far too much to point out, but I’d like to share some of the more interesting insights, claims, and conclusions I personally got from this book, especially as it might line up or disagree with my own understanding of CH XIII.  I present them in no particular order, but they should be useful for coming up with some new insights for those who want to more deeply dive into the ideas, theories, and models of CH XIII.

• The are are three views in the CH about how humanity can come to know God.  One view is that humanity can come to know God “by studying the perfection of the stars in the sky” i.e. astrology (e.g. CH III).; a second is that one cannot come to know God through studying the sensible/perceptible cosmos but only through the intellectual/noetic cosmos via the divine Mind (Nous).  Both of these views presuppose an innate ability for humanity to know God; however, the view of CH XIII denies this presupposition and says, quite explicitly, that “no one can be saved before being born again” (CH XIII.1), that without regeneration/rebirth into a new divine body there is no possibility of coming to know God at all.  Otherwise, without such regeneration/rebirth, one is held in a form that is forever cut off from such knowledge.
• The corporeal, material body we have is born from the twelve signs of the Zodiac, each sign contributing a particular body part (e.g. Aries the head or Virgo the belly) as well as a particular vice, a particular irrational tormentor of matter.  The divine, noetic body, on the other hand, which is the body into which one is reborn “when God wishes” (CH XIII.2), is composed of ten holy powers.  The process of rebirth in CH XIII is that of constructing a new immaterial body composed from “parts” in which one can live immortally as Nous, much as how we are living now in a material body composed from “parts” in which we live mortally.
• Because of this, unlike CH I, there is no notion in CH XIII of a primordial “fall of man”, where humanity was once able to know God directly but fell into matter and corporeal bodies which cut it off from such a direct knowing of God.  Rather, CH XIII has the notion that souls are part of the cosmos and naturally come to occupy corporeal bodies, and so there was never a “fall” to begin with; rather than us falling to the bottom of the barrel, we were naturally made at the bottom already, and so while we must still climb up, it’s not that we’re climbing back up because there’s no prior time at which we were already up there.  This means that there is no notion in CH XIII of us having “original sin” or otherwise deserving to suffer—it’s just the way we’re made down here through ultimately natural processes.
• In short: humanity is not inherently divine, but becomes divine through rebirth.  Revelation is not a remembering of some innate knowledge, but coming into something never-before-experienced.  We are not at fault through hubris or some other crime for our fallen state because we never fell; rather, we are made the way we are by the Zodiac, and it is on us to seek the help of God in undoing the creation of the Zodiac into something new beyond it.  The problem that CH XIII aims to solve is not that we are bound to some fatalistic, deterministic cosmos from which we need to be set free, but rather that we are born into bodies that prevent us from knowing and being with God directly, which just so happens to keep us bound in a fatalistic, deterministic cosmos.  In order to escape the power of the Zodiac into which and by which we are born, we must be born again without the Zodiac.
• Although the twelve irrational tormentors are chased away by the ten holy powers, it’s not that there’s some notion of a power chasing off a particular tormentor; otherwise, there’d be little numeric or numerological sense in something in greater numbers being routed by something in lesser numbers.  Rather, the twelve irrational tormentors are considered as one whole group, which is chased out by another group composed of ten powers; CH XIII phrases this as one group against another group, rather than twelve forces against ten forces.  Said another way: that there are twelve signs of the Zodiac is just an illusion that obscures the whole Zodiac’s own essential unity, and so the twelve tormentors are really just one—just as the ten holy powers are.
• There’s something of a notion of “the Hermetic elect” in CH XIII that we don’t see in other texts: the whole process of rebirth (which is essential for coming to know God and achieve salvation) entirely dependent on God, such that not only do we need the help of God in initiating or accomplishing it but that it is itself done by God, and moreover, God chooses who is to be reborn and when.  This sort of approach is not unheard of in some mystery religions of the classical world, and is certainly extant in some gnostic groups regarding who is or isn’t able to be saved.  Whether this is technically true or indicative of only some limited number of people ever being able to be saved is not able to be known at this time.
• Like other texts in the CH, Nous is the means by which we can come to know and “see” Divinity.  However, unlike other texts which claim/presuppose that all humans are born with Nous (even if inactive and requiring activation) or which can be given Nous, CH XIII claims that one becomes Nous (not unlike the view of the latter part of CH X), and (unlike CH X) this can be done while still alive in this life before dying.  In this, God (as Nous itself) is only able to be known through the act of noeîn, which is only possible to those who are themselves Nous.
• Although many people (myself included) like coming up with elaborate hierarchies or diagrams illustrating the various connections or relationships various hypostases or concepts might have (think of all those elaborate charts common in Neoplatonic texts or commentaries to illustrate what does what, where, and how), CH XIII is super vague when it comes to distinguishing or defining terms like “nous”, “logos”, “soul”, “spirit”, and the like.  For the most part, these terms are interchangeable in CH XIII, preventing the declaration of a clear hierarchy of concepts in CH XIII.  This is totally fine; after all, the purpose of CH XIII is less to establish a fixed cosmological or theological doctrine and more a ritual reenactment and clarification of the process and qualities of salvation.  This is especially prominent with the term “Logos”, which in other Hermetic texts “is the divine revealer who brings to man the truth about God” and “also functions as the creator of the world and as the mediator between God and man” (per Grese), but in CH XIII is equivalent to “Nous” while also being the means by which one offers “spoken sacrifices” to God, the “divine agent involved in prayer”.
• Grese points out the same difficulties as I have before regarding the ten powers, not as being some simple set of ten but rather as seven plus three, where the final three (Goodness with Life and Light) are not virtues like the first seven (knowledge, joy, self-control, etc.).  The use of ten seems more numerological than cosmical here, with the first seven powers being an echo of some sort of cosmic/divine ascent through the spheres as in CH I.
• Salvation, in CH XIII, consists of undoing the material body of the Zodiac and creating a divine immortal body.  This is done, not as in CH I by an ascent of the soul through the spheres, but a descent of divinity (via the ten divine powers) into a human.  Prior to rebirth, humanity is dominated by the twelve irrational tormentors; after rebirth, the ten holy powers.  Once reborn, the one who is reborn is no longer bound to the body and, thus, to the body’s sense-perceptions alone or to the turbulence and confusion of the physical world in general.
• Tat’s question in CH XIII.14 that Hermēs rebukes indicates that being reborn is not a surefire guarantee of salvation.  Unlike some gnostic beliefs that suggest that those with an element of the divine cannot lose it, Hermēs’ reply suggests that even one having been (re)born into a divine, immortal, immaterial body of Nous can still do wrong and become profaned.  This is, however, also unlike the Christian demand to continue living a holy life after having been baptized, because for the Christian, even once reborn, one is still inhabiting the material body which can still sin; for the author of CH XIII, this is not the case, because once reborn, what happens in or with the physical body is ultimately rendered irrelevant once one is reborn into something that so utterly transcends it.
• Hermēs reply in CH XIII.15 (“that you hasten to strike the tent is good”) to Tat’s request to be taught the hymn of the powers is super weird.  Here, given what we know of the divine ascent from CH I.26, this means that such a prayer can only truly be given by the Nous or otherwise out of or beyond the material body, even if the material body participates in it.  Moreover, this hymn is not something that Poimandrēs taught Hermēs; rather, it is something that Hermēs naturally learns to do on his own, but having been authorized to do so by Poimandrēs due to Hermēs’ own rebirth.  In other words, the hymn itself is not a revelation, but something that naturally arises as a result of revelation.
• The hymn of CH XIII is almost certainly pulled from some other source, and is also compiled from two or more different sources, such that CH XIII.17 seems to be a more public thing sung by a Hermetic community, while CH XIII.18 being an elaboration of the themes from earlier in CH XIII, and Tat’s own praise in CH XIII.21 being something abbreviated (if not partially lost) from some other kind of hymning/praising/thanksgiving.  This is evident not only in changes of style but also changes in how the speaker considers a fundamental monism or dualism of the divine world with/against the material one.  There may well be corruption in the hymn of CH XIII.18, too, not just elsewhere, given how it seems to contain some of the holy powers from earlier in CH XIII but not all of them, suggesting that the hymn was not, as a whole, independently composed apart from the rest of CH XIII.
• Based on how Hermēs calls on the holy powers (the “parts” that compose his divine, immortal, noetic body into which he was reborn) within him to sing with and through him indicates that they have not “taken him over”; Hermēs still retains his own individuality and will, and is not merely a puppet for the powers.  Rather, these powers come together to hymn God, and it is truly them that is singing the hymn through Hermēs; after all, it is that the holy powers have come into him, and in him do they sing.  This is why Hermēs calls on them to sing, in addition to drawing them down so that they become/remain active.
• Although the hymn of CH XIII is, on the whole, one of thanksgiving, certain bits of the hymn don’t make sense; why should the hymn request for salvation and illumination if they’ve already been achieved through rebirth, that rebirth being that which authorizes/permits one to sing such a hymn in the first place?  Grese hypothesizes that CH XIII is indicative of a cultic practice where those who have already been initiated through rebirth remember and emphasize the meaning and method of such rebirth, as a part of which they sing such a hymn, so as to remain in such an enlightened, saved state (not unlike the final two requests of the Prayer of Thanksgiving at the end of the Perfect Sermon).
• The final statement of Hermēs (“you know yourself and our father intellectually”, νοερῶς ἔγνως σεαυὸν καἰ τὸν πατέρα τὸν ἡμέτερον) is something of a “holy word”, a sort of Hermetic formula equivalent to the Delphic maxim “know thyself”.  This is something that probably can be used to ritually conclude either an initiation or a general Hermetic celebration of gnōsis generally.  However, while in CH I (in agreement with various gnostic traditions) “know thyself” is a matter of someone recognizing the divine already present within themselves and coming to realize their own inherent divinity, CH XIII reinterprets this to mean that knowing oneself is only possible once there is something at all to meaningfully know, which is God and which is facilitated only by and with God.