David King is a Christian apologist known (inter alia) for co-writing with William Webster the three volume book, Holy Scripture: The Ground and Pillar of Our Faith. I'm in a Facebook group with him and he posted some interesting quotes from the early church fathers regarding the Holy Spirit in response to someone who seemed to have doubted the Holy Spirit's full Deity. Below I'll reproduce some of his comments:
Ambrose (c. 339-97) commenting on Acts 5:4: Not only does the Scripture in this place clearly bear witness to the θεότης of the Holy Spirit, that is the Godhead, but the Lord himself also said in the Gospel: ‘For the Spirit is God’ (Jn 3:6). See Fathers of the Church, Vol. 44, Saint Ambrose: Theological and Dogmatic Works, On the Holy Spirit, Book III, Chapter 10, §59 (Washington D.C.: The Catholic University of America Press, 1963), p. 174.
Basil of Caesarea (A.D. 329-379): We glorify the Holy Ghost together with the Father and the Son, from the conviction that He is not separated from the Divine Nature; for that which is foreign by nature does not share in the same honors. All who call the Holy Ghost a creature we pity, on the ground that, by this utterance, they are falling into the unpardonable sin of blasphemy against Him. I need use no argument to prove to those who are even slightly trained in Scripture, that the creature is separated from the Godhead. The creature is a slave; but the Spirit sets free. The creature needs life; the Spirit is the Giver of life. The creature requires teaching. It is the Spirit that teaches. The creature is sanctified; it is the Spirit that sanctifies. Whether you name angels, archangels, or all the heavenly powers, they receive their sanctification through the Spirit, but the Spirit Himself has His holiness by nature, not received by favour, but essentially His; whence He has received the distinctive name of Holy. What then is by nature holy, as the Father is by nature holy, and the Son by nature holy, we do not ourselves allow to be separated and severed from the divine and blessed Trinity, nor accept those who rashly reckon it as part of creation. Let this short summary be sufficient for you, my pious friends. From little seeds, with the co-operation of the Holy Ghost, you will reap the fuller crop of piety. “Give instruction to a wise man and he will be yet wiser.” I will put off fuller demonstration till we meet. When we do, it will be possible for me to answer objections, to give you fuller proofs from Scripture, and to confirm all the sound rule of faith. For the present pardon my brevity. I should not have written at all had I not thought it a greater injury to you to refuse your request altogether than to grant it in part. NPNF2: Vol. VIII, Letters, Letter 159, To Euraterius and his daughter, §2.
Moreover, taken in context (contrary to the claims of Roman apologists), Athanasius himself is a witness against your claim. In the citation below, while commenting on this passage from Ad Serapion 1.28, Shapland explains: “It is important to understand what Athanasius is appealing to here. The passage from ad Adelph. which we have already quoted makes it clear that tradition to Athanasius is not an indefinite source of knowledge, independent of Scripture. Not only does he insist upon the sufficiency of Scripture (de Syn. 6 and elsewhere), he does not strictly distinguish tradition and Scripture. See Robertson, Intro. lxxiv. Nor is he appealing to the authority of earlier Fathers. . . .The real direction of Athanasius’s appeal is to be understood from the citation of the baptismal formula later on. It is of the faith as delivered, expounded, and confessed in baptism that he is thinking. Thus the τεθεμελίωται of the succeeding sentence is taken up again in the preamble to the citation of Matthew 28:19 by τοῦτον θεμέλιον τιθέναι, making it plain that the θεμέλιον is nothing other than the threefold Name as invoked in baptism. See C. R. B. Shapland, trans., The Letters of Athanasius Concerning the Holy Spirit, Ad Serapion 1.28 (New York: The Philosophical Library, 1951), footnote # 28², pp. 133-134. Thus Athanasius is not appealing to some unwritten oral tradition, but the testimony of Scripture in Matthew 28…
Athanasius (297-373): These sayings concerning the Holy Spirit, by themselves alone, show that in nature and essence he has nothing in common with or proper to creatures, but is distinct from things originate, proper to, and not alien from, the Godhead and essence of the Son; in virtue of which essence and nature he is of the Holy Triad, and puts their stupidity to shame.
But, beyond these sayings, let us look at the very tradition, teaching, and faith of the Catholic Church from the beginning, which the Lord gave, the Apostles preached, and the Fathers kept. Upon this the Church is founded, and he who should fall away from it would not be a Christian, and should no longer be so called. There is, then, a Triad, holy and complete, confessed to be God in Father, Son, and Holy Spirit, having nothing foreign or external mixed with it, not composed of one that creates and one that is originated, but all creative; and it is consistent and in nature indivisible, and its activity is one. The Father does all things through the Word in the Holy Spirit. Thus the unity of the Holy Triad is preserved. Thus one God is preached in the Church, ‘who is over all, and through all, and in all’—‘over all’, as Father, as beginning, as fountain; ‘through all’, through the Word; ‘in all’, in the Holy Spirit. It is a Triad not only in name and form of speech, but in truth and actuality. For as the father is he that is, so also his Word is one that is and God over all. And the Holy Spirit is not without actual existence, but exists and has true being. Less than these (Persons) the Catholic Church does not hold lest she sink to the level of the modern Jews, imitators of Caiaphas, and to the level of Sabellius. Nor does she add to them by speculation, lest she be carried into the polytheism of the heathen. And that they may know this to be the faith of the Church, let them learn how the Lord, when sending forth the Apostles, ordered them to lay this foundation for the Church, saying: ‘Go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.’ (Matthew 28:19). C. R. B. Shapland, trans., The Letters of Athanasius Concerning the Holy Spirit, Ad Serapion 1.27-28 (New York: The Philosophical Library, 1951), pp. 133-136.
Niceta of Remesiana (335-415): However, it is possible that these benign and beneficent qualities do not rouse our mind to an understanding of the power of the Holy Spirit. Let us turn, then, to aspects more terrifying. It is written in the Acts of the Apostles that the disciple Ananias sold his possessions and by fraud kept back part of the price, and, bringing the rest in place of the whole, laid it at the feet of the Apostles. He offended the Holy Spirit whom he had thought to deceive. Now, what did St. Peter without hesitation say to him? ‘Ananias, why has Satan tempted thy heart, that thou shouldest lie to the Holy Spirit?’ Then he added: ‘Thou hast not lied to men, but to God.’ And being struck by the power of Him whom he had hoped to deceive, he expired. What does St. Peter here mean by the Holy Spirit? He clearly gives the answer when he says: ‘Thou hast not lied to men, but to God.’ It is clear that one who lies to the Holy Spirit lies to God; therefore, one who believes in the Holy Spirit believes in God. The wife of Ananias, who connived at the lie, also joined him in his death. FC, Vol. 7, Writings of Niceta of Remesiana, The Power of the Holy Spirit, §17 (New York: Fathers of the Church, Inc., 1949), p. 37. Migne attributed this work mistakenly to Niceta the Bishop of Aquileia. See FC, Vol. 7, Introduction (New York: Fathers of the Church, Inc., 1949), p. 6.
Augustine (354-430): When the apostle said, Do you not know that your body is the temple in your midst of the Holy Spirit whom you have from God, and you are not your own? For you have been purchased at a great price, he immediately goes on to say, Glorify God, then, in your body (1 Cor 6:19-20). There he showed with utter clarity that the Holy Spirit is God and that he should be glorified in our body as if in his temple. The apostle Peter said to Ananias, Have you dared to lie to the Holy Spirit? And to show that the Holy Spirit is God, he said, You have not lied to men, but to God (Acts 5:3-4). John E. Rotelle, O.S.A., ed., The Works of Saint Augustine, Arianism and Other Heresies, Answer to Maximinus the Arian, Book II:XXI.1, Part 1, Vol. 18, trans. Roland J. Teske, S.J. (Hyde Park: New City Press, 1995), p. 304.
Epiphanius of Salamis (310/320-403): Peter also makes us certain of the Holy Spirit by saying to Ananias, “Why hath Satan tempted you to lie to the Holy Ghost? You have not lied to men, but unto God,” for the Spirit is of God and not different from God. Frank Williams, trans., The Panarion of Epiphanius of Salamis: Book II and III (Sects 47-80, De Fide) Section IV, 59. Against the impure “Purists,” 10,1 (Leiden: E.J. Brill, 1994), p. 109.
Gregory of Nazianzus (329/330-389): But now the swarm of testimonies [i.e. scriptural testimonies] shall burst upon you from which the Deity of the Holy Ghost shall be shewn to all who are not excessively stupid, or else altogether enemies to the Spirit, to be most clearly recognized in Scripture. Look at these facts:—Christ is born; the Spirit is His Forerunner. He is baptized; the Spirit bears witness. He is tempted; the Spirit leads Him up. He works miracles; the Spirit accompanies them. He ascends; the Spirit takes His place. What great things are there in the idea of God which are not in His power? What titles which belong to God are not applied to Him, except only Unbegotten and Begotten? For it was needful that the distinctive properties of the Father and the Son should remain peculiar to Them, lest there should be confusion in the Godhead Which brings all things, even disorder itself, into due arrangement and good order. Indeed I tremble when I think of the abundance of the titles, and how many Names they outrage who fall foul of the Spirit. He is called the Spirit of God, the Spirit of Christ, the Mind of Christ, the Spirit of The Lord, and Himself The Lord, the Spirit of Adoption, of Truth, of Liberty; the Spirit of Wisdom, of Understanding, of Counsel, of Might, of Knowledge, of Godliness, of the Fear of God. For He is the Maker of all these, filling all with His Essence, containing all things, filling the world in His Essence, yet incapable of being comprehended in His power by the world; good, upright, princely, by nature not by adoption; sanctifying, not sanctified; measuring, not measured; shared, not sharing; filling, not filled; containing, not contained; inherited, glorified, reckoned with the Father and the Son; held out as a threat; the Finger of God; fire like God; to manifest, as I take it, His consubstantiality); the Creator-Spirit, Who by Baptism and by Resurrection creates anew; the Spirit That knoweth all things, That teacheth, That bloweth where and to what extent He listeth; That guideth, talketh, sendeth forth, separateth, is angry or tempted; That revealeth, illumineth, quickeneth, or rather is the very Light and Life; That maketh Temples; That deifieth; That perfecteth so as even to anticipate Baptism, yet after Baptism to be sought as a separate gift; That doeth all things that God doeth; divided into fiery tongues; dividing gifts; making Apostles, Prophets, Evangelists, Pastors, and Teachers; understanding manifold, clear, piercing, undefiled, unhindered, which is the same thing as Most wise and varied in His actions; and making all things clear and plain; and of independent power, unchangeable, Almighty, all-seeing, penetrating all spirits that are intelligent, pure, most subtle (the Angel Hosts I think); and also all prophetic spirits and apostolic in the same manner and not in the same places; for they lived in different places; thus showing that He is uncircumscript.
30. They who say and teach these things, and moreover call Him another Paraclete in the sense of another God, who know that blasphemy against Him alone cannot be forgiven, and who branded with such fearful infamy Ananias and Sapphira for having lied to the Holy Ghost, what do you think of these men? Do they proclaim the Spirit God, or something else? Now really, you must be extraordinarily dull and far from the Spirit if you have any doubt about this and need some one to teach you. NPNF2: Vol. VII, The Fifth Theological Oration On the Holy Spirit, Oration XXXI, §29-30.
