This question is not new. Textbooks of Church History usually refer to this as the “filioque clause controversy.” (Filioque is Latin for “and the Son.”) The creedal citation referenced actually appears in the Creed of the Council of Constantinople (381). The Creed of the Council of Nicea (325) ended, “And in the Holy Spirit.” At that time, however, a group called the Pneumatomachi (i.e. “the killers of the Spirit) denied the divinity of the Holy Spirit, and consequently shattered the mystery of the Holy Trinity. In response, the Council of Constantinople (381) affirmed the Creed of Nicea and added the last section, which clarified the role of the Holy Spirit. In the original Greek text, this last section reads, “And in the Holy Spirit, the Lord and Giver of life, who proceeds from the Father, who together with the Father and the Son is worshipped and glorified….” Thus, the Creed professed at Mass was actually promulgated by the Council of Constantinople and is officially titled “The Nicene-Constantinopolitan Creed.”
The Creed was later translated into Latin with the addition, “who proceeds from the Father and the Son” (filioque). This filioque clause first appeared in the translation issued by the Council of Toledo, Spain, in 589. During the Carolingian Dynasty, Charlemagne petitioned Pope Leo III at the Synod of Aachen (809) to have the filioque clause accepted universally; the Pope declined, hesitating to add anything, however appropriate, to the official text of a conciliar creed. Several Church fathers argued that the meaning of the filioque clause was no different from the meaning of the succinct teaching, “Father through the Son.” Nevertheless, the filioque clause was added to the creed recited in the Roman Mass (Latin Rite) by Pope Benedict VIII (1024), but was not used in the liturgy of the Eastern Rites.
The filioque clause has been cited as one of the official causes of the schism between the Western and Eastern Churches in 1054. Although this point was later officially remedied by the Churches at the Councils of Lyons II (1274) and Florence (1439), the reconciliation was short lived. The filioque clause still remains a point of contention between Roman Catholics and Orthodox Christians. (As an aside, this is one reason why the Orthodox Churches call themselves “the orthodox,” for they contend that the Roman Catholic Church tampered with the Creed.)
Why then did the Church add the filioque clause? Remember, during those early councils, like Nicea and Constantinople, the Church guided by the Holy Spirit was struggling to clarify the mystery of Christ, the Incarnate Word of God, and thereby the Trinity. We believe in one God, divinely revealed as Father, Son, and Holy Spirit. All three persons of the Trinity are equal, are distinct, share the same divine nature, and exist from all eternity.
With this is mind, examine Sacred Scripture. In Sacred Scripture, the Holy Spirit referred to as both the Spirit of the Son (Galatians 4:6) and the Spirit of Christ (Romans 8:9, Philippians 1:19). He is also called Spirit of the Father (Matthew 10:20) and the Spirit of God (I Corinthians 2:11). These citations show the same relationship of the Holy Spirit to the Son as to the Father.
The Spirit is sent by both the Father and the Son as taught by Jesus Himself: “When the Paraclete comes, the Spirit of truth who comes from the Father– and whom I myself will send from the Father– will bear witness on my behalf” (John 15:26). “It is much better for you that I go. If I fail to go, the Paraclete will never come to you; whereas if I go, I will send him to you” (John 16:7). “This much have I told you while I was still with you; the Paraclete, the Holy Spirit whom the Father will send in my name, will instruct you in everything, and remind you of all that I told you.” (John 14:25-6).
Finally, our Lord Himself attested to the intimate bonding and sharing between the Persons of the Trinity: “When He comes, however, being the Spirit of Truth, He will guide you to all truth. He will not speak on His own but will speak only what He hears, and will announce to you the things to come. In doing this He will give glory to me, because He will have received from me what He will announce to you. All that the Father has belongs to me. That is why I said that what He will announce to you He will have from me” (John 16:13-15). Given this basis in Scripture, the Church teaches that the Holy Spirit proceeds from both the Father and the Son.
The Council of Florence (1439) summed it up well: The council defined that the Holy Spirit is eternally from both the Father and the Son, shares the same divine nature as Father and Son, and proceeds eternally in one “spiration” from Father and Son as from one “principle.” Moreover, the council stated that since the Father has given to the eternally begotten Son everything, “we define that the explanatory words ‘Filioque‘ have been added in the Symbol [creed] legitimately and with good reason for the sake of clarifying the truth and under the impact of a real need at that time.”
In all, never was the addition of the filioque clause meant to change the meaning or teaching of the Creed, but rather to clarify it from misinterpretation. The dispute, therefore, is actually more a matter of semantics.