Through the Spirit
Now, one is the Holy Spirit, and he is proclaimed singly. He is joined through the one Son to the one Father, and through himself, he completes the famed and blessed Trinity. That he is not ranked in the multitude of creation but rather, uniquely named makes clear enough his kinship with the Father and the Son.
On the Holy Spirit, by St. Basil the Great
1 Corinthians 14: 24 But if all prophesy, and an unbeliever or an uninformed person comes in, he is convinced by all, he is convicted by all. 25 And thus the secrets of his heart are revealed; and so, falling down on his face, he will worship God and report that God is truly among you.
To prophesy is a gift that comes from the Spirit, yet it demonstrates that God is among the believers. The two, Father and Spirit, are inseparable in this work. Can it be the case, then, that the Spirit is of creation?
Acts 5: 9(a) Then Peter said to her, “How is it that you have agreed together to test the Spirit of the Lord?
Acts 5: 4(b) You have not lied to men but to God.
Testing the Spirit is lying to God. Sins against God and the Holy Spirit are the same thing. There is unity and indivisibility in every work of the Holy Spirit from the Father and the Son. The Lord’s presence in the flesh is from the Spirit, as is His anointing. The Spirit was present when Jesus was tempted in the desert. The Church was clearly and undeniably founded through the Holy Spirit.
1 Corinthians 2: 10 But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God. 11 For what man knows the things of a man except the spirit of the man which is in him? Even so no one knows the things of God except the Spirit of God.
Again, the Father and the Spirit are inseparable. Just as the Son is begotten, the Spirit is the breath of God’s mouth – a mouth not like ours, but appropriate to God, and the Spirit a breath not like ours but as a living substance.
While the kinship is thus made clear, the manner of its existence remains unspeakable.
A sentiment I share, and one, if lived by in the early centuries, that might have prevented certain divisions.
Throughout Scripture, we see names given to the Spirit, the greatness of His works, and the kindness He bestows on us.
John 4: 24(a) God is Spirit
Job 33: 4(a) The Spirit of God has made me
Exodus 31: 3 And I have filled him with the Spirit of God, in wisdom, in understanding, in knowledge, and in all manner of workmanship
His works are both great and uncountable. The working of miracles and the gifts of healing are all through the Holy Spirit; demons are driven out through Him; the devil is hindered when the Spirit is present; the deliverance from sins is the grace of the Spirit.
Our kinship with God comes through the Spirit:
Galatians 4: 6 And because you are sons, God has sent forth the Spirit of His Son into your hearts, crying out, “Abba, Father!” 7 Therefore you are no longer a slave but a son, and if a son, then an heir of God through Christ.
The Spirit of the Lord is referenced several times as well, not as if He is a slave or a creature, but as one with equal authority to God the Father. Unlike creatures (including even angels), the Spirit is not limited to being in only one place at a time. He worked in both Daniel and Habakkuk in Babylon; He was simultaneously with Jeremiah in stocks and Ezekiel at the Chebar.
Basil continues by expanding on non-scriptural (and by this, he does not mean anti-scriptural) sources for our understanding of the Holy Spirit:
Of the dogmas and proclamations that are guarded in the Church, we hold some from the teaching of the Scriptures, and others we have received in mystery as the teachings of the tradition of the apostles.
If we reject the non-scriptural customs as insignificant, we would lose very vital parts of the Gospel.
Both hold the same power with respect to true religion.
I know many reject this idea. For me, I hold that Scripture is the only infallible source, but this does not make it the only source. I think about this often, as should be obvious from my writing.
Why do we not accept and teach Arianism? Those who were Arians had numerous proof-texts at their disposal, just as did those who taught orthodox Christology. Try having a proof-text debate with a Jehovah’s Witness; they are far better catechized than most Trinitarian Christians.
So, why one and not the other instead? It seems to me that we accept orthodox Christology and the Trinity because this is how the early Church understood what they were taught; it is how they were taught to interpret Scripture. More on this in the Epilogue below.
Conclusion
Basil’s closing chapter is entitled “Explanation of the present state of the churches.” It seems no matter how much some want to present the historic Church as unified, it appears to be not much different than what we see today.
To what, then, will we compare the present condition?
He compares it to a naval battle: two fleets crashing together to fight it out; ships driven by a violent storm, clouds and fog obscuring everything – hiding friend from foe. All resulting in terrible disorder and confusion.
This is how he describes the Arian attack against orthodox Christianity. A war, fracturing into many parts, stormier than the waves of the sea; irreconcilable hatred.
Such chaos did not end once Arianism was defeated:
We have in common with each other that we hate our common opponents, but whenever the enemies leave, then we harm each other as enemies.
Now we fight with each other; personal hostility deteriorates into public warfare. The glory of lording over one’s opponent is preferred to the common good of all.
Just like today.
Epilogue
And, as if coming to my comments above about using only Scripture for such battles:
Inspired Scripture cannot mediate between these two, and apostolic traditions arbitrate the disputes that they have with each other.
Absent this, everyone becomes their own theologian. It is built on arrogance. The result – in his time and even after the defeat of Arianism:
In everyone love has grown cold, and fraternal communion destroyed. Even the name of unity is unknown, and loving correction has disappeared. Nowhere is there Christian mercy; nowhere a sympathetic tear.
Just like today.
For transparency, many times throughout this book Basil was as polemical as the most polemical of any modern-day apologist for their tradition / denomination and against the “other.” In other words, he didn’t consistently practice what he was preaching here at the conclusion….

"And, as if coming to my comments above about using only Scripture for such battles:
Inspired Scripture cannot mediate between these two, and apostolic traditions arbitrate the disputes that they have with each other.
Absent this, everyone becomes their own theologian. It is built on arrogance. "
I guess I would say several things about this. From my understandings there isn't 1 apostolic tradition a person can go to. There isn't an "answer key" that a believer can go to, to find which doctrine is true or false.
Inspired Scripture is the infallible source of information. So anyone who wants to know the truth has to go to the infallible source. Church theology can help along the way by comparing which theology best explains or conforms to ALL scripture. But there is no human standard that stands above God's Word telling us what to think about it. That kind of thinking creates its own source of arrogance. Anyone trying to learn the Bible can become arrogant and there are examples across all denominations.
My experience is that I am least arrogant when I 1) hold what the Bible says above any human explanation of it including my own, 2) submit myself to the commands in the Bible, judge myself by Biblical principles, focus on my own need for repentance and salvation, and 3) ask the Holy Spirit to lead me to truth but know that any attempt I will make will have some amount of error in it.
Great thoughts Bionic! The Unity of God, One in Three is the ultimate model of what Christ's church should be, but isn't. It is to me the most frustrating thing about "Christianity" today. I have experienced up close and personal in a vibrant rather small local church -- blown to bits, most scattered. I often ponder Ephesians 4:1-6. I believe if all truly believing Christians could act as one, the world would believe. John 17:20-21. But how?