The Filioque
Tertullian of Carthage
I believe the Spirit to proceed from no other source than from the Father through the Son [Against Praxeas 4 (c. A.D. 218)].
St. Gregory Thaumaturgus
And there is one Holy Spirit, having his subsistence from God, and being made manifest by the Son, to men: image of the Son, perfect image of the perfect; life, the cause of the living; holy fount; sanctity, the supplier of sanctification; in whom is manifested God the Father, who is above all and in all, and God the Son, who is through all [Declaration of Faith (c. A.D. 265)].
St. Hilary of Poitiers
Concerning the Holy Spirit... there is no need to speak, because we are bound to confess him, proceeding, as he does, from Father and Son [The Trinity 2:29 (c. A.D. 357)].
But I cannot describe him, whose pleas for me I cannot describe. As in the revelation that your only-begotten was born of you before times eternal, when we cease to struggle with ambiguities of language and difficulties of thought, the one certainty of his birth remains; so I hold fast in my consciousness the truth that your Holy Spirit is from you and through him, although I cannot by my intellect comprehend it [ibid., 12:56].
Didymus the Blind
As we have understood discussions... about the incorporeal natures, so too it is now to be recognized that the Holy Spirit receives from the Son that which he was of his own nature. So too the Son is said to receive from the Father the very things by which he subsists. For neither has the Son anything else except those things given him by the Father, nor has the Holy Spirit any other substance than that given him by the Son [The Holy Spirit 37 (c. A.D. 371)].
St. Epiphanius of Salamis
The Father always existed and the Son always existed, and the Spirit breathes from the Father and the Son [Man Well-Anchored 75 (A.D. 374)].
St. Basil of Caesarea
One, moreover, is the Holy Spirit, and we speak of him singly, conjoined as he is to the one Father through the one Son, and through himself completing the adorable and blessed Trinity [The Holy Spirit 18:45 (A.D. 375)].
Thus the way of the knowledge of God lies from one Spirit through the one Son to the one Father, and conversely the natural goodness and the inherent holiness and the royal dignity extend from the Father through the only-begotten to the Spirit. Thus there is both acknowledgment of the hypostases and the true dogma of the monarchy is not lost [ibid., 18:47].
St. Ambrose of Milan
That is the fount of the Holy Spirit, for the Spirit is life, as the Lord says: “The words I speak unto you are Spirit and life [Jn 6:64]” [The Holy Spirit 1:15:172 (A.D. 381)].
The Holy Spirit, when he proceeds from the Father and the Son, does not separate himself from the Father and does not separate himself from the Son [ibid., 1:11:120].
St. Gregory of Nyssa
For there, with the Father, unoriginated, ungenerated, always Father, the idea of the Son as coming from him yet side by side with him is inseparably joined; and through the Son and yet with him, before any vague and unsubstantial conception comes in between, the Holy Spirit is found at once in closest union [Against Eunomius 1:26 (c. A.D. 382)].
St. Augustine of Hippo
That which is given has him for a beginning by whom it is given, since it has received from no other source what proceeds from him; it must be admitted that the Father and the Son are a beginning of the Holy Spirit, not two beginnings; but as the Father and Son are one God, and one Creator, and one Lord relative to the creature, so are they one beginning relative to the Holy Spirit. But the Father, the Son, and the Holy Spirit is one beginning relative to the creature, as also one Creator and one God [The Trinity 5:14:15 (c. A.D. 408)].
The one from whom the Holy Spirit principally proceeds. And therefore I have added the word principally, because we find that the Holy Spirit proceeds from the Son also [ibid., 15:17:29].
Why, then, should we not believe that the Holy Spirit proceeds also from the Son, when he is the Spirit also of the Son? For if the Holy Spirit did not proceed from him, when he showed himself to his disciples after his Resurrection he would not have breathed upon them, saying, “Receive the Holy Spirit” [Jn 20:22]. For what else did he signify by that breathing upon them except that the Holy Spirit proceeds also from him [Tractates on John 99:7 (A.D. 416–417)].
St. Cyril of Alexandria
Since the Holy Spirit when he is in us effects our being conformed to God, and he actually proceeds from the Father and Son, it is abundantly clear that he is of the divine essence, in it in essence and proceeding from it [Treasury of the Holy Trinity, thesis 34 (c. A.D. 424)].
Athanasian Creed
That we worship one God in Trinity and Trinity in unity... The Father uncreated, the Son uncreated, and the Holy Spirit uncreated. The Father incomprehensible, the Son incomprehensible, and the Holy Spirit incomprehensible. The Father eternal, the Son eternal, and the Holy Spirit eternal, and yet they are not three eternals but one eternal [Athanasian Creed (c. A.D. 425)].
St. Fulgence of Ruspe
Hold most firmly and never doubt in the least that the same Holy Spirit who is Spirit of the Father and of the Son proceeds from the Father and the Son [The Rule of Faith 54 (A.D. 524)].
St. John of Damascus
I say that God is always Father since he has always his Word [the Son] coming from himself and, through his Word, the Spirit issuing from him [Dialogue Against the Manicheans 5 (c. A.D. 728)].
Likewise we believe also in one Holy Spirit, the Lord and giver of life... God existing and addressed along with Father and Son: uncreated, full, creative, all-ruling, all-effecting, all-powerful, of infinite power, Lord of all creation and not under any Lord; deifying, not deified; filling, not filled; shared in, not sharing in; sanctifying, not sanctified; the intercessor, receiving the supplications of all; in all things like the Father and Son, proceeding from the Father and communicated through the Son [Exposition of the Orthodox Faith 1:8 (c. A.D. 746)].
And the Holy Spirit is the power of the Father revealing the hidden mysteries of his divinity, proceeding from the Father through the Son in a manner known to himself, but different from that of generation [ibid., 12].
