word expressed orally
word immanent in the imagination
word in the discursive intellect
word naturally stored in our mind
The word expressed orally is physical and not directly mental at all; so it is unsuitable for comparison. This is the same with the word immanent in the imagination. The word in the discursive intellect is not, like the first two, a matter of sounds; but it begins and ends. Thus, Gregory proposes, the word most analogous to the Divine Word is a word "in the sense of the word naturally stored up within our mind, whereby we have come into being from the one who created us according to his own image, namly that knowledge which is also coexistent with the mind" (ch. 35). In the Divine Word, of course, the Word expresses perfectly the goodness of its Source, so it is everything the goodness of God is, and can thus be called the Son so that we might recognize him as both derived from the Father and his own hypostasis.
Now, a word comes with a spirit, so the Divine Word must have a Holy Spirit proceeding with Him from the Father. But again there are several different things we could mean by 'spirit', going with the several different things we could mean by 'word':
spirit accompanying the spoken (breath)
spirit accompanying the immanent word
spirit accompanying the discursive word
spirit accompanying the natural word
And for the same reasons that the Word must be understood as a word in the sense of the word naturally in us, the Spirit must be understood as spirit in the sense of a spirit accompanying the natural word. This is a sort of love, for, as Palamas says, "that Spirit of the supreme Word is like an ineffable love of the Begetter towards the ineffably begotten Word himself" (ch. 36). This Love is also the love of the Begotten toward the Begetter; but the mode in which it is, is different, in that the Son possesses this Love as "proceeding from the Father together with him and as resting connaturally in him" (ch. 36). The Holy Spirit is common (koinon) to Father and Son as a sort of pre-eternal joy of the Father and the Son (he is adapting this from Proverbs 8:30). He is thus sent to the faithful from both, although He proceeds from the Father alone.
This is reflected "in the relation of the mind to the knowledge which exists perpetually from it and in it, in that this love is from it and in it and proceeds from it together with the innermost word" (ch. 37). Gregory suggests that even those who lack the discipline for clear self-knowledge can see something of this in our insatiable desire for knowledge. Of course, the image of the Trinity in the human mind is only an imperfect echo of the Holy Trinity itself, and we call the Holy Spirit not just Love but Spirit and Paraclete in order to recognize Him as accompanying the Word but also as his own hypostasis. Thus the infinite goodness of God is not three goodnesses, but one goodness as a supreme Trinity, three true and perfect hypostases undivided.
This basic image of mind, word, spirit is found in all intellectual natures, including angels. But one of the distinctive and ingenious features of Gregory's discussion is that there is one way in which, for all our flaws and imperfections, human beings are more in the image of God than even angels. Angels do not possess the spirit or love as life-giving. 'Life-giving', of course, is a key attribute of the Holy Spirit, being found in the Nicene Creed. Gregory argues, however, that human beings do possess a spirit that is life-giving, because our basic, natural love for our bodies keeps the body alive. "Thereby," he says (in ch. 38),
it is shown to men of understanding that man's spirit, the life-giving power in his body, is intellectual love; it is from the mind and the word, and exists in the word and the mind, and possesses both the word and the mind within itself Through it the soul naturally possesses such a bond of love with its own body that it never wishes to leave it and will not do so at all unless force is brought to bear on it externally from some very serious disease or trauma.
This image of God remains in us even though we do not act or think in a manner worthy of people in God's image. Because we are even more in the image of God than the angels (even if in other ways angels surpass us in dignity), the human mind "ought to preserve its proper rank and take its place after God alone and be subject, subordinate and obedient to him alone, and look to him alone and adorn itself with perpetual remembrance and contemplation of him and with most fervent and ardent love for him" (ch. 40). Drawn to God in this way, it will possess the image and likeness of God in an even more glorious sense, because it will have been made divine, and in this will both love God and itself more truly; because he who loves wrongdoing hates his own soul by breaking apart the triadic communion which makes him in God's image.
Quotations are from Gregory Palamas, The One Hundred and Fifty Chapters, Robert E. Sinewicz, tr. PIMS (Toronto: 1988).