Scripturally, the center of the debate is John 15:26, where Christ says that the Spirit of truth “proceeds from the Father.” This text became especially important for the Orthodox position because it explicitly names the Father as the one from whom the Spirit proceeds. At the same time, the broader New Testament also speaks of the Spirit as the “Spirit of Christ” in Romans 8:9, the “Spirit of His Son” in Galatians 4:6, and as being sent by the Son in John 15:26 and John 16:7. This is why the disagreement is not over whether the Son is related to the Spirit. Both East and West affirm that the Spirit is fully divine, distinct from the Father and the Son, and inseparable from the Son’s saving work. The controversy is over whether the Spirit’s eternal hypostatic procession should be confessed as “from the Father alone” or “from the Father and the Son.”
The original Creed associated with the Council of Constantinople in 381 confessed the Holy Spirit as “the Lord, the giver of life, who proceeds from the Father.” The Catholic Catechism itself acknowledges that the Filioque “does not appear in the Creed confessed in 381 at Constantinople,” and that its introduction into the Latin liturgical Creed remains “a point of disagreement with the Orthodox Churches.” This matters because the Creed was not a private theological essay. It was a conciliar confession of the Church’s faith, received liturgically and dogmatically by East and West.
Historically, the Filioque appears in the Latin West gradually. It became associated with anti-Arian and later anti-Adoptionist concerns, especially in Spain and the Frankish world. Western theologians used the phrase to emphasize the full divinity of the Son: if the Spirit is the Spirit of the Son, and if the Son sends the Spirit, then the Son is not a creature beneath the Father but shares fully in the divine life. The North American Orthodox-Catholic Consultation notes that since at least the late sixth century many Western Christians used a Latin version of the Creed with the added phrase “and from the Son.”
Yet the history was not simple. Rome itself did not immediately adopt the addition into its liturgical Creed. Around 809–810, Pope Leo III affirmed the orthodoxy of the Western doctrine but resisted inserting the Filioque into the Creed of 381. According to the same Orthodox-Catholic consultation, Leo approved the term for teaching and personal confession, but disapproved its insertion into the Creed itself; the tradition of the silver shields says he displayed the Creed in Greek and Latin at St. Peter’s without the addition. The Creed with the Filioque was later sung in a papal Mass in 1014, after Emperor Henry II petitioned Pope Benedict VIII, and from that point its liturgical use in Rome carried broader papal sanction in the Latin Church.
The Orthodox theological objection centers on what is often called the monarchy of the Father. In classical Eastern theology, the Father is the single personal source, cause, or fountainhead within the Trinity. The Son is eternally begotten of the Father, and the Spirit eternally proceeds from the Father. This preserves the distinction of the divine Persons without dividing the one divine essence. St. John of Damascus states that the Holy Spirit proceeds from the Father and is communicated “through the Son,” but he explicitly says, “we do not speak of the Spirit as from the Son.” He later clarifies the point even more sharply: the Spirit proceeds through the Son from the Father, “for the Father alone is cause.”
This distinction between “from the Father through the Son” and “from the Father and the Son” is crucial. Many Eastern fathers could speak of the Spirit being manifested, given, sent, or shining forth through the Son. Orthodoxy does not deny the Son’s eternal relationship to the Spirit. But it rejects the idea that the Son is a second source or cause of the Spirit’s hypostatic existence. From the Orthodox perspective, the Filioque risks blurring the unique personal properties of the Trinity: the Father as unbegotten cause, the Son as begotten, and the Spirit as proceeding. This is why Patriarch Photius objected so strongly in the ninth century, arguing that the Filioque threatened the monarchy of the Father and confused the relations among the divine Persons.
The Roman Catholic defense is more nuanced than simply saying “the Spirit has two sources.” Official Catholic teaching explicitly denies that there are two independent principles in God. The Catechism says that the Spirit proceeds from the Father and the Son “as from one principle and through one spiration.” It also says the Father remains the “first origin” of the Spirit and that the Eastern formula “from the Father through the Son” can be understood as complementary when properly interpreted. So, at its strongest, the Catholic argument is that the Filioque safeguards the Son’s consubstantial communion with the Father, while still avoiding the claim that the Father and Son are two separate causes.
But for Orthodoxy, the problem is not solved merely by saying “one principle.” The Orthodox concern is that the Father’s unique hypostatic role as cause is being extended to the Son. Even if Rome says the Father and Son are not two separate sources, Orthodoxy asks whether the Son is now being included in the Father’s personal property of being cause. If so, the issue is not only terminology but Trinitarian order. In Orthodox theology, whatever is common to the divine nature belongs equally to Father, Son, and Holy Spirit; whatever is personal distinguishes the Persons. Therefore, if “cause of the Spirit” is personal to the Father, it cannot also belong to the Son without confusing personal properties.
The canonical issue is just as serious. The Council of Ephesus in 431 forbade composing or presenting a “different faith” as a rival to the faith established at Nicaea. Orthodox Christians have long appealed to this canon as evidence that the Creed should not be altered unilaterally. Catholics often reply that the West did not create a rival faith but clarified the same apostolic faith in Latin. Orthodoxy answers that even if the theological intention were orthodox, the Creed of the ecumenical councils belonged to the whole Church, not to one regional tradition or bishop. Thus, the problem is both doctrinal and ecclesiological: What does the Church confess about the Spirit, and who has the authority to revise the common Creed?
The Filioque therefore became a symbol of deeper East-West tensions. It involved language, theology, liturgy, conciliar authority, papal authority, and the growing alienation between Greek East and Latin West. It was not the only cause of the Great Schism, but it became one of its clearest doctrinal flashpoints. The Orthodox objection is not that the Son has no relationship to the Spirit, nor that the Spirit is somehow less connected to Christ. The objection is that the Creed’s original wording, grounded in John 15:26 and received by the ecumenical councils, protects the Father as the one personal source within the Trinity.
A fair conclusion is this: Roman Catholicism defends the Filioque as a legitimate doctrinal development meant to confess the Son’s full divinity and communion with the Father. Eastern Orthodoxy rejects it as a unilateral alteration of the Creed and as a theological formula that risks compromising the monarchy of the Father. The controversy endures because it is not about one word alone. It is about the Trinity, the Creed, and the authority of the Church to guard the faith once delivered.
Scripture:
John 15:26
John 14:26
John 16:7
Romans 8:9
Galatians 4:6
1 Corinthians 2:10–12
John 20:22
Acts 2:33
Primary / Ancient and Ecclesial Sources
Niceno-Constantinopolitan Creed, AD 381.
Council of Ephesus, AD 431, Canon 7.
St. John of Damascus, An Exposition of the Orthodox Faith, Book I, Chapter 8.
Second Council of Lyons, AD 1274.
Council of Florence, AD 1439.
Catechism of the Catholic Church, §§245–248.
North American Orthodox-Catholic Theological Consultation, The Filioque: A Church-Dividing Issue? 2003.
Copyable links
BibleHub, John 15:26:
https://biblehub.com/john/15-26.htm
Catechism of the Catholic Church, §§245–248:
https://www.vatican.va/archive/ENG0015/__P17.HTM
Council of Ephesus, Canon 7:
https://www.newadvent.org/fathers/3810.htm
St. John of Damascus, On the Orthodox Faith, Book I:
https://www.newadvent.org/fathers/33041.htm
North American Orthodox-Catholic Theological Consultation, The Filioque: A Church-Dividing Issue?:
https://www.assemblyofbishops.org/ministries/ecumenical-and-interfaith-dialogues/orthodox-catholic/filioque-a-church-dividing-issue
USCCB PDF version of the same consultation document:
https://www.usccb.org/resources/filioque-a-church-dividing-issue.pdf
Catholic Encyclopedia, Filioque:
https://www.newadvent.org/cathen/06073a.htm