The New Testament and the Nicene Creed are deeply entangled with each other. The wording and the concepts in the Nicene Creed come from the New Testament—in fact, one of the most important debates at the Council of Nicaea concerned whether it is proper to include a word in the Nicene Creed that does not occur in the New Testament. On the other hand, at the time that the Church issued the official canon of the New Testament, it customarily compared writings to the Nicene Creed to determine if they were orthodox. So you are correct if you say that the Nicene Creed proceeds from the New Testament, and you are correct if you say that the New Testament is certified by the Nicene Creed.
By affirming certain books as Holy Scripture, it does not follow that the Church rejected or even banned all other writings. The Church continued to use the other writings, if they were orthodox, but not with scriptural authority.
Here is a brief, comparative history of both the New Testament canon and the Nicene Creed.
By this time, all of the writings we include in our New Testament are in their present form and are in use by Christians.
We have Christian documents dating from this time or earlier that quote the gospels, the Pauline epistles, and the Epistle to the Hebrews as authoritative.
In Rome, Marcion the heretic draws up a list of what he thinks are the authoritative books of the New Testament. Marcion emphasizes God’s love but is anti-Semitic. He recognizes only Paul as the faithful transmitter of the truth, claiming that the other apostles missed the message.
Marcion’s New Testament includes the Epistle to the Hebrews and the Pauline epistles, except the epistles to Timothy and Titus. He includes Luke, after editing it to remove everything Jewish. He rejects Matthew, Mark, and John.
The four gospels, Matthew, Mark, Luke, and John, are so well established in the Church that the pagan public knows about them and ridicules Christians for not getting their story straight. In Assyria, Tatian publishes the first harmony of the gospels to demonstrate that they are not in conflict with each other. It is called the Diatessaron, a Greek musical term that means four-part harmony. Tatian’s Diatessaron was used for scripture readings in Syriac churches until the fifth century.
By this time, Christian writers have been using all of our New Testament books as holy scripture, equal in authority with the Old Testament.
In some areas, a few people object to the following books, mainly because of uncertain authorship. The main reason Revelation is included in this list is because of its heavy use by heretics:
A few people felt that the following books should be part of the New Testament:
Epistle of Barnabas
The Epistles of Clement
The Shepherd of Hermas
Bishop Alexander of Alexandria indulges his presbyters in a theological debate, preferring that they come to an orthodox conclusion on their own, without him having to impose it on his authority. The debate gets out of hand. Among the presbyters, Arius leads the heterodox
faction. He even spreads his views through popular songs. Alexander issues a letter condemning Arius, but when another bishop agrees with Arius, the dispute has to be escalated higher.
The Ecumenical Council of Nicaea convenes to settle two controversies: Arianism and the date of the Pascha (Easter). It adopts the Nicene Creed
to combat Arianism
by affirming the equality of the Father and the Son, and makes the Creed a mandatory test of orthodoxy. It rejects anything that does not conform to the Nicene Creed.
Bishop Athanasius issues his annual Easter Letter, the main purpose of which was to announce the dates of the holy days in the coming year. In 367, he includes list of the books of scripture, which is the New Testament as we have it today. He is not making a new list, he is 1only using his authority to endorse long-standing practice. In some areas, some people still object to Revelation because they feel it is conducive to the heresies defeated at Nicaea.
The Ecumenical Council of Constantinople convenes to settle the controversies of Apollinarianism and Montanism. It expands the Nicene Creed to include statements about the Holy Spirit and to affirm the equality of the Persons of the Trinity.
A church council in Rome affirms the same list as Athanasius. It vindicates Revelation as part of scripture, despite its misuse by heretics. All later Church actions agree with this ruling.
The Ecumenical Council of Ephesus reaffirms the Nicene Creed and makes it unchangeable by local councils.
A local council in Toledo, Spain, adds the filioque
clause to the Nicene Creed.
Bishop Paulinus of Aquilea defends the filioque clause at a council in Friuli.
In Jerusalem, western monks use the filioque
clause in their worship. Eastern monks accuse them of irregularities. The dispute is escalated to the western monks’ patriarch
, Bishop Leo of Rome [Pope Leo III]. Leo approves of the sentiment, but not the change in the creed. Leo has the original creed engraved on silver tablets and places them in Peter’s tomb.
The Great Schism
Rome excommunicates the Eastern Church.
The Patriarch of Constantinople retaliates by excommunicating Rome.
The filioque clause is in universal use in the Roman Catholic Church.
The western Council at Lyons, France, makes the filioque clause an official part of the Nicene Creed for the Roman Catholic Church.
The western Council in Florence, Italy attempts to reunite the Eastern Orthodox and Roman Catholic Churches. The Eastern Orthodox offer to concede the filioque
clause if the Roman Catholics concede the papacy, making the pope only the ‘first among equals’ with the other patriarchs
. The Roman Catholics refuse the papacy deal, a lone Eastern Orthodox bishop stands on principle about the filioque clause, and the reunion fails. (The Eastern Orthodox reason that if this Council had succeeded, it would have been a true Ecumenical Council, and that would have given it the authority to amend the Nicene Creed.)
The Church of England and the Protestant Churches inherit the filioque clause from Rome.
The Great Schism Ends—More or Less
On 7 December, Pope Paul VI and Patriarch Athenagoras meet. They issue a joint statement in which they deplore the events that led to the schism of AD 1054 and revoke their mutual excommunication. However, they do not establish intercommunion or resolve the filioque controversy.
You can read more details about the Nicene Creed.