Well, on the Volume 6 of this long, long series. And I think I'm not going to bother going every day through this, though I might start by hitting every individual text in the book--or at the very least every author. Then again I might not, we'll have to see how they hold up...
Gregory Thaumaturgus: Introduction; Part I: Acknowledged Writings: A Declaration of Faith
Apparently, Gregory's title "Thaumaturgus" is not really so much a last name as it is a descriptor, just like John's "Chrysostom" means "silver-tongued," it's not a family name. He's no relation to the pagan orator Dio Chrysostom, other than in sharing his eloquence. Apparently a series of legends about Gregory as a miracle-worker grew up in the century or so after his death, and so the name "Thaumaturgus" got attached to this student of Origen. And while we (with the editors in the introduction) might question some of the stories about him, we can be thankful there's a fairly easy way to distinguish him from all the other Gregories in the ancient church--and of course we can be thankful for his faithfulness and skill in thinking carefully about the faith.
The Declaration of Faith is a pretty clear precursor to the later Creeds, and to that end it's worth simply citing in full. There's no reason not to read this and every reason to appreciate the solid orthodoxy of this part of the early church. (Source)
There is one God, the Father of the living Word, who is His subsistent Wisdom and Power and Eternal Image: perfect Begetter of the perfect Begotten, Father of the only-begotten Son.
There is one Lord, Only of the Only, God of God, Image and Likeness of Deity, Efficient Word, Wisdom comprehensive of the constitution of all things, and Power formative of the whole creation, true Son of true Father, Invisible of Invisible, and Incorruptible of Incorruptible, and Immortal of Immortal and Eternal of Eternal.
And there is One Holy Spirit, having His subsistence from God, and being made manifest by the Son, to wit to men: Image of the Son, Perfect Image of the Perfect; Life, the Cause of the living; Holy Fount; Sanctity, the Supplier, or Leader, of Sanctification; in whom is manifested God the Father, who is above all and in all, and God the Son, who is through all.
There is a perfect Trinity, in glory and eternity and sovereignty, neither divided nor estranged.
Wherefore there is nothing either created or in servitude in the Trinity; nor anything superinduced, as if at some former period it was non-existent, and at some later period it was introduced.
And thus neither was the Son ever wanting to the Father, nor the Spirit to the Son; but without variation and without change, the same Trinity abideth ever.