And such as the Only-begotten is, such is the Holy Spirit.
Then, again, He is so by virtue of life-giving, of imperishability, of unvariableness, of everlastingness, of justice, of wisdom, of rectitude, of sovereignty, of goodness, of power, of capacity to give all good things, and above them all life itself.
He is so by being everywhere, being present in each, filling the earth, residing in the heavens, shed abroad upon supernatural powers, filling all things according to the deserts of each, Himself remaining full, being with all who are worthy, and yet not parted from the Holy Trinity.
He ever “searches the deep things of God,” ever “receives” from the Son, ever is being “sent,” and yet not separated, and being “glorified,” and yet He has always had glory.
It is plain, indeed, that one who gives glory to another must be found himself in the possession of superabundant glory; for how could one devoid of glory glorify another? Unless a thing be itself light, how can it display the gracious gift of light?
So the power to glorify could never be displayed by one who was not himself glory, and honour, and majesty, and greatness. Now the Spirit does glorify the Father and the Son.
Neither does He lie Who saith, “Them that glorify Me I glorify” (cf. 1 Sam. 2:30). And “I have glorified Thee” (John 17:4), is said by our Lord to the Father.
And again He says, “Glorify Thou Me with the glory which I had with Thee before the world was” (John 17:5). The Divine Voice answers, “I have both glorified, and will glorify again” (John 12:28).
You see the revolving circle of the glory moving from Like to Like.
The Son is glorified by the Spirit; the Father is glorified by the Son; again the Son has His glory from the Father; and the Only-begotten thus becomes the glory of the Spirit.
For with what shall the Father be glorified, but with the true glory of the Son. And with what again shall the Son be glorified, but with the majesty of the Spirit?
In like manner, again, Faith completes the circle, and glorifies the Son by means of the Spirit, and the Father by means of the Son.
Gregory of Nyssa (c 335 – after 394): On the Holy Spirit.