In order to understand procession of the Holy Spirit we must first talk about Nicene-Constantinople creed and their authors. Namely first Athanasius and Ephiphanius, and after Cappadocian fathers.
The creed itself (1) cites John 15:26 which says:
“But when the Helper comes, whom I shall send to you from the Father, the Spirit of truth who proceeds from the Father, He will testify of Me.”
The longer creed (1) from Epiphanius states and elaborates further, quoting John 16:14:
“Holy Spirit will receive of Mine and will proclaim Him to you.“
Athanasius of Alexandria says:
“For if they thought correctly of the Word, they would think soundly of the Spirit also, who proceeds from the Father, and is proper to the Son, is from him given to the disciples and all who believe in him.” (2)
Epiphanius of Salamis says:
“He proceeds from the Father and receives of the Son, and is not different from the Father and the Son” (3)
What did author intend to say with this quote?
In order to comprehend all of these words we first must simply state that in order to understand why we say only Father can proceed, we must also understand what does word proceed, and even word beget, mean;
Now both of those words mean “To be caused” or “To Originate” , and from our church fathers he have learned that “the nature of that difference we in no wise understand", and that, “the generation of the Son from the Father and the procession of the Holy Spirit are simultaneous “ (4)
What we do know is that every single person has it’s own unique unsharable property, like Gregory of Nyssa says:
“The characteristics of the Father's Person(hypostasis) cannot be transferred to the Son or to the Spirit, nor on the other hand, can that of the Son be accommodated to one of the others, or the property of the Spirit be attributed to the Father and the Son.” (5)
Also from Gregory Nazianzen:
“Teach also that we must not make the Father subject to [another] cause, lest we posit a "first of the First," and thus overturn the divine existence; nor should we say that the Son or the Holy Spirit is without the cause, unless we take away the Father's special characteristics.” (6)
What does this mean?
This means that every single person in this triad has it’s own mode of being, which is basically what hypostasis means. And to prove that every person has it’s own mode of being here is what Maximus the Confessor says:
“For who, if deprived not always of grace according to reason, is unaware that every nature, existing in its essence, is distinguished by its own peculiar characteristics? In this way, both the mode of its specific existence and the difference by which it is purely separated from other natures, demonstrate the being of that essence. When the distinctive properties are removed from it, either it will not exist at all, or what was not becomes so, if indeed, through the complete removal of its distinctive properties, it could be said to endure. For it is natural for that which is subject to natural characteristics to perish when the peculiar properties are corrupted. Idioms tend to perish with natures.” (7)
Fathers mode of being is to be the Cause, Sons mode of being is to be begotten from the Father, Spirits mode of being is to proceed from the Father. Here are church fathers that say this exactly:
Gregory Nazianzen says:
“But if all that the Father has belongs likewise to the Son, except Causality; and all that is the Son's belongs also to the Spirit, except His Sonship, and whatsoever is spoken of Him as to Incarnation for me a man, and for my salvation, that, taking of mine, He may impart His own by this new commingling.” (8)
Basil the Great says:
“And it is not from this source alone that our proofs of the natural communion are derived, but from the fact that He is moreover said to be of God; 2 Corinthians 1:12 not indeed in the sense in which all things are of God, but in the sense of proceeding out of God, not by generation, like the Son, but as Breath of His mouth.” (9)
Epiphanius of Salamis says:
“The Son is begotten of the Father and the Spirit proceeds from the Father, though in some ineffable way the Trinity exists in an identity of its glory and is incomprehensibly a Son, and likewise a Holy Spirit, with a Father; nor does the Trinity ever cease from the same eternity.” (10)
Cyril of Alexandria in two places says:
"We have heard that He[Spirit] proceeds from the Father, and by the limits set by theologians and blessed men, we eagerly accept the procession, exceeding the creation" (11)
"Therefore, He called the Spirit from God, teaching that it has existence from the Father, and its existence is of that nature" (12)
There is emphasize from the Father, because this is their unique property of both Son and Spirit, because they are both from the Father. However, we cannot simply ignore the fact that they all unianimously say that Spirit ‘receives’ of/trough the Son. So to understand what this means we need to see how church fathers used the word receive when talking about Holy Spirit receiving through him.
Here is what Cyril of Jerusalem says:
“And the Father indeed gives to the Son; and the Son shares with the Holy Ghost. For it is Jesus Himself, not I, who says, All things are delivered unto Me of My Father; and of the Holy Ghost He says, When He, the Spirit of Truth, shall come, and the rest.…He shall glorify Me; for He shall receive of Mine, and shall shew it unto you. The Father through the Son, with the Holy Ghost, is the giver of all grace; the gifts of the Father are none other than those of the Son, and those of the Holy Ghost; for there is one Salvation, one Power, one Faith; One God, the Father; One Lord, His only-begotten Son; One Holy Ghost, the Comforter.” (13)
As we can see, receiving means Son sharing with the Son divine attributes, or activities, that they together (Father, Son and Spirit) will give to the creation. And similarly Son shares this also with the Holy Spirit eternally, so that he is not alien to the Spirit but that he is connected to the Spirit.
There is also another way of using through the Son, and John Damascus tells us how it is also appropriate to use it.
John Damascus says:
“And we confess that He is manifested and imparted to us through the Son. For He breathed upon His Disciples, says he, and said, Receive ye the Holy Spirit.” (14)
To manifest simply means to be made known, or is known.
In order to explain this manifestation we shall go to fire analogy.
John Scotus Eriugena says:
“So it is, and an inquiry into natures teaches thoroughly that it cannot be otherwise. Must we then say that that brightness which proceeds from the fire through the nascent ray has two causes? For although it proceeds from the fire through the ray, yet the fire only is its cause, not the ray. For as the ray itself would not subsist through itself if it were not born of its cause, which is fire, so there would be no brightness through the ray if it did not first proceed from the cause of the ray. You see, then, that no reason requires that the brightness proceed from two causes, although it is understood to flow from the fire through the ray; but nature, our teacher, herself declares that from one and the same cause both the ray is born and the brightness proceeds, and that therefore the brightness proceeds from the fire as well as from the ray.” (15)
Here word proceed is better translated as “shines forth”. However that is not the point. I don’t want to argue words but concepts.
Reason why I brought up this quote is to say that just like Sun or Fire produce ray and brightness and ray does not produce brightness nor other way around. So in the same way Father produces both Son and Spirit and they don’t produce each other. Because their special property is to be from the Father.
Now if you say that Spirit proceeds from both and then give me a latin church fathers where they say that he does, I am not going to ignore it or say that they did not teach filioque. In fact I will agree and say that they do. However which type of filioque they taught is the real question here. And we know which kind of filioque that is, economic/manifesting. I have proven that already with a quote above, however if you want more proof…here is a proof:
Maximus the Confessor says:
“For the procession they [the Romans] brought the witness of the Latin Fathers, as well, of course, as that of St Cyril of Alexandria in his sacred study on the Gospel of St John. On this basis they showed that they themselves do not make the Son Cause (Aitia) of the Spirit. They know, indeed, that the Father is the sole Cause of the Son and of the Spirit, of one by generation and of the other by procession — but they explained that the latter shines forth through the Son, and they showed in this way the unity and the immutability of the essence.” (16)
You are very free to disagree and say that he does not disagree, or that this is not actually from him. However I have a quote from a latin church father, namely Anastasius the Librarian that says:
“Furthermore, we have translated, from the letter of the same St. Maximus addressed to the priest Marinus, a passage concerning the procession of the Holy Spirit, wherein he notes that the Greeks had brought up a charge against us to no purpose, since we do not claim that the Son is cause or principle of the Holy Spirit, as they suppose; but, being not unaware of the unity of substance of the Father and the Son, we say that, in just the way he proceeds from the Father, in that very same way he proceeds from the Son, taking ‘procession,’ doubtless, in the sense of ‘mission.’ By this pious interpretation Maximus instructs those who are unlearned* in the two languages to be at peace, since in fact he teaches both us and the Greeks that, in one way, the Holy Spirit does proceed from the Son, and, in another way, he doesn’t, while he points out the difficulty of expressing the idiom of one language in that of another.” (17)
In conclusion: Church fathers did not believe in procession of the Spirit from the Son, but “solely from the Father”. (17)
Here is one more quote to fully give an idea of what was said until now from Saint Basil the Great:
“As, therefore, the Creator Word strengthened the heaven, in the same way, the Spirit, which is from God, who proceeds from the Father (that is, from His mouth), so that you may not judge it as something external and created, but as having the ὑπόστασιν from God[Father]” (18)
Question is asked, What is the mark of Spirits hypostatic individuation? To have hypostasis from the Father; or that is to say to proceed from the Father.
Here is also my florilegium for pro-Orthodox filioque:
Anti-Filioque Florilegium
This is a small list of quote mines that I have collected, in this instance without any context [but some].
(1) Καὶ εἰς τὸ Ἅγιον Πνεῦμα πιστεύομεν, ἐκ τοῦ Πατρὸς ἐκπορευόμενον, καὶ ἐκ τοῦ Υἱοῦ λαμβανόμενον καὶ πιστευόμενον. (And we believe in the Holy Ghost, proceeding from the Father [longer → and received [receiving] from the Son, and believed])
(2) Saint Athanasius of Alexandria, To Serapion on The Holy Spirit
(3) Saint Epiphanius of Salamis, Panarion, Against Sabellians, 4.1, p125
(4) Saint John Damascus, Exposition of the Orthodox Faith, translated by Rev. S. D. F. Salmond, Book 1, Chapter 8, p567
(5) Saint Gregory of Nyssa, Treaties on the Lord's Prayer, Sermon 3
(6) Saint Gregory of Nazianzen, Orations 25
(7) Saint Maximus the Confessor, Letter 7, PG 81 436A
(8) Saint Gregory Nazianzen, Oration 34, PG 36.252A
(9) Saint Basil the Great, On The Holy Spirit 18.46
(10) Saint Epiphanius of Salamis, Panarion, Against Pneumatomachi, p501
(11) Saint Cyril of Alexandria, On the Holy Trinity, PG75, 1176C
(12) Saint Cyril of Alexandria, On the Holy Trinity, PG75, 1181A
(13) Saint Cyril of Jerusalem, Lecture XVI On the Article, And in One Holy Ghost, the Comforter, Which Spake in the Prophets (Philip Schaff, NPNF2-07)
(14) Saint John Damascus, Exposition of the Orthodox Faith, translated by Rev. S. D. F. Salmond, Book 1, Chapter 8, p571
(15) John Scotus Eriugena, Periphyeson Book II, 608D
(16) Saint Maximus the Confessor, Letter to Marinus of Cyprus, PG 91, 136 A-B
(17) Anastasius the Librarian, To John the Deacon, PL 129, 560-561 and PG 91, 136B
(18) Saint Basil the Great, Hom. in Ps. 32, 4, PG 29, 333B