Anti-Trinitarians often accuse those who believe in the Trinity of believing the Creeds over or against or instead of simply believing the Bible. This objection assumes that the Creeds do not faithfully teach what the Bible teaches. Although Catholic and Orthodox Christians typically view the Creeds as having dogmatic authority, evangelical Protestants typically do not. We believe the Creeds inasmuch as, and insofar as, we find them in agreement with the Bible.

The composition and use of creeds actually began before the New Testament books were written. Biblical scholars have detected in certain passages of the New Testament early creedal statements that the authors incorporated into their writings. The formalized style and wording of these statements make them stand out from their contexts. Two of these are found in 1 Corinthians, one of the earliest New Testament writings (ca. 54):

One God, the Father, from whom [are] all things and we for him, and
One Lord, Jesus Christ, through whom [are] all things and we through him. (1 Cor. 8:6)

That Christ died for our sins
in accordance with the Scriptures,
That he was buried,
That he was raised on the third day
in accordance with the Scriptures, and
That he appeared to Cephas, then to the twelve. (1 Cor. 15:3-5)

There are four major documents from the early centuries of Christianity commonly called creeds. Their customary names are the Apostles Creed, the Nicene Creed, the Definition of Chalcedon (or Chalcedonian Creed), and the Athanasian Creed. The Apostles Creed was probably not written by apostles but its contents and wording closely follow texts in the apostolic writings of the New Testament. In fact, the Apostles Creed combines and expands on the two creedal statements quoted above from 1 Corinthians:

I believe in God, the Father almighty, Creator of heaven and earth,
and in Jesus Christ, his only Son, our Lord,
who was conceived by the Holy Spirit,
born of the Virgin Mary,
suffered under Pontius Pilate,
was crucified, died and was buried;
on the third day he rose again from the dead;
he ascended into heaven,
and is seated at the right hand of God the Father almighty;
from there he will come to judge the living and the dead.
I believe in the Holy Spirit,
the holy catholic Church,
the communion of saints,
the forgiveness of sins,
the resurrection of the body,
and life everlasting. Amen.

The Nicene and Chalcedonian Creeds were produced by the councils at Nicaea in the fourth century and at Chalcedon in the fifth century. These councils are known as “ecumenical” councils because they represented a cross-section of Christian churches throughout most of the known world. The Nicene Creed is essentially an expanded version of the Apostles Creed. The Athanasian Creed was not written by Athanasius or even during his lifetime and was not a creed produced through or adopted by one of the councils of Christian leaders held in the early centuries. Although its explanation of the Trinity is generally acceptable, the document should not be included among the ecumenical creeds.

In what follows, I will quote in full the Nicene Creed and the Definition of Chalcedon, along with biblical citations enclosed in brackets, and with no interpretive or explanatory comments. No doubt anti-Trinitarians will object to the way some of these biblical passages are understood within the Trinitarian theological framework. Nevertheless, this exercise ought to demonstrate beyond any reasonable doubt that the intent of the Creeds is simply to state in a formal, systematic, confessional way what its authors understood the Bible to teach about the Father, Son, and Holy Spirit, and especially about the person of Jesus Christ as both fully God and fully human.

The Nicene Creed (381)

We believe in one God, the Father, the Almighty, Maker of heaven and earth, and of all things visible and invisible. [Matt. 23:9; Acts 4:24; 17:24; 1 Cor. 8:6a; 2 Cor. 6:18; Heb. 11:3; Rev. 21:22]
And in one Lord, Jesus Christ [1 Cor. 8:6b; 12:4; Eph. 4:5],
the only-begotten Son of God [John 1:12, 18; 3:16, 18; 1 John 4:9],
begotten of the Father before all ages [John 1:14, 18; 5:26; 6:57; 17:5; Gal. 4:4],
God of God [John 1:1, 18; Titus 2:10, 13; 2 Peter 1:1-2],
Light of Light [John 1:4-5; Heb. 1:3],
true God of true God [John 1:1, 18; Col. 2:9; 1 John 5:20],
begotten, not made [John 1:14, 18],
being of one substance with the Father [John 1:14; Heb. 1:3],
by whom all things were made [John 1:3, 10; Col. 1:16-17; Heb. 1:2, 10];
who for us men, and for our salvation, came down from heaven [John 13:3; 16:28],
and was incarnate [John 1:14; Rom. 8:3; 1 John 4:1]
by the Holy Spirit of the Virgin Mary [Matt. 1:18-25; Luke 1:35],
and was made man [Phil. 2:6-7],
and was crucified also for us under Pontius Pilate [Matt. 27; Mark 15; Luke 23; John 18-19].
He suffered [Matt. 16:21 par.; 17:12 par.; Luke 22:15; 24:26, 46; Acts 1:3; 3:18; 1 Pet. 3:18]
and was buried [Matt. 27:57-66 par.; Acts 13:29; 1 Cor. 15:4],
and the third day he rose again according to the Scriptures [Luke 24:44-46; 1 Cor. 15:5],
and ascended into heaven [Acts 1:9-11],
and sits at the right hand of the Father [Mark 14:62; Luke 22:69; Acts 2:33, 34; 5:31; 7:55-56; Rom. 8:34; Eph. 1:20; Col. 3:1; Heb. 1:3, 13; 8:1; 10:12; 12:2; 1 Pet. 3:22].
And he shall come again with glory [Matt. 16:27; Heb. 9:26-28; Titus 2:13; etc.]
to judge both the living and the dead [Matt. 25:31-46; John 5:22-23, 28-29; Acts 10:42; 17:31; 2 Cor. 5:10; 2 Thess. 1:7-8; Rev. 2:23];
whose kingdom shall have no end [Luke 1:33; Eph. 1:19b-21; Heb. 1:8; Rev. 11:15].
And we believe in the Holy Spirit [Matt. 28:19],
the Lord [2 Cor. 3:16-17]
and Giver of Life [Ps. 104:30; Ezek. 37:14; John 3:5-8; 6:63; Rom. 8:2, 6, 10-11; 2 Cor. 3:6; Gal. 5:25],
who proceeds from the Father [John 14:16, 26; 15:26; 16:7],
who with the Father and the Son together is worshipped and glorified [Matt. 28:19; Phil. 3:3; cf. Matt. 12:31-32; Mark 3:29],
who spoke by the prophets [Acts 1:16; 28:25-27; Heb. 3:7-11; 10:15-17; 1 Pet. 1:11].
And we believe one holy catholic and apostolic church [Eph. 2:18-22; 3:5-6; 4:4].
We acknowledge one baptism for the remission of sins [Luke 24:47; Acts 2:38; 22:16; Eph. 4:5].
And we look for the resurrection of the dead [John 5:29; 11:24-25; Acts 4:2; 23:6; 24:15; Rom. 8:11; 1 Cor. 15; etc.],
and the life of the world to come [Mark 10:30; Luke 18:30; 20:34-35; etc.].
Amen. 

The Definition of Chalcedon (451)

We, now, following the holy Fathers [Matt. 16:18; 28:20; 2 Tim. 2:2; Jude 3]
all with one consent [1 Cor. 1:2; Eph. 4:5, 11-16],
teach men to confess one and the same Son, our Lord Jesus Christ [2 Cor. 11:4; Eph. 4:5],
the same perfect in Godhead [theotēti, Grk.; deitate, L.] [Col. 2:9; Heb. 1:3]
and also perfect in manhood [Phil. 2:7-8; Heb. 5:8-9];truly God [John 1:1, 18; 20:28; Acts 20:28; Rom. 9:5; Tit. 2:13; Heb. 1:8; 2 Pet. 1:1; 1 John 5:20]
and truly man [Acts 2:22; 1 Cor. 15:21; 1 Tim. 2:5; Heb. 2:5-9],
of a reasonable [logikēs] soul [Matt. 26:38-39; John 11:33; 12:27; Acts 2:27, 31]
and body [Matt. 26:12; 27:56-59; John 2:21; Heb. 10:10];
consubstantial [homoousion] with the Father according to the Godhead [John 1:1; 10:30; 14:9; Col. 1:19, cf. 2:9; Heb. 1:3];
and consubstantial with us according to the Manhood [John 1:14; Acts 2:31; Rom. 1:3; 8:3-8; 1 John 4:2];
in all things like unto us, without sin [Heb. 2:14, 17; 4:15; 5:8-9];
begotten before all ages of the Father according to the Godhead [John 1:14, 18; 5:26; 6:57; Gal. 4:4],
and in these latter days [Heb. 1:1-2],
for us and for our salvation [Luke 2:10-11],
born of the Virgin Mary, the Mother of God [theotokos], according to the Manhood [Matt. 1:18-25; Luke 1:27, 31, 34-37, 43; 2:7];
one and the same Christ, Son, Lord, Only-Begotten [Luke 2:11; John 1:14-18],
to be acknowledged in two natures [phuseōn] [Rom. 1:3-4; 9:5; Phil. 2:6-8; Col. 2:9],
inconfusedly, unchangeably, indivisibly, inseparably [Heb. 1:10-12; 13:8];
the distinction of natures being by no means taken away by the union, but rather the property of each nature being preserved, and concurring in one Person [prosōpon] and one Subsistence [hupostasin] [Luke 8:22-25; John 8:57-58; 1 Cor. 2:8; Gal. 4:4; Phil. 2:6-8; Heb. 2:14-18],
not parted or divided into two persons [Eph. 4:5],
but one and the same Son, and only-begotten [monogenē], God the Word, the Lord Jesus Christ [John 1:1-3, 14-18];
as the prophets from the beginning have declared concerning him [Heb. 1:1-13];
and the Lord Jesus Christ himself has taught us [Matt. 28:19-20; John 3:16],
and the Creed of the holy Fathers has handed down to us [1 Tim. 3:16; Jude 3].