Someone somewhere in the forums has written that the Doctrine of the Triune God head began at the Council of Nicea in the fourth century AD.(325 AD). This is not unique to Muslim understanding, but so called christian sects (who are really not christian at all) who deny the Deity of Christ, have said the same thing.
Without relooking at all the Old Testament credentials for the One and Only God, to have three distinct Persons .. Father, Son and Holy Spirit, here is what the early church said ...
To know what the early church said of Him, we need to look at the period immediately after and within the first century of his death and resurrection.
1. Ignatius (died 117 AD).. a disciple of the apostle John and Bishop of Antioch who died a martyrs death in Rome by being thrown to wild animals
He wrote four letters to the churches which are not part of the Bible but which in their opening sentences say "... Jesus Christ Our God" Each letter, to the Ephesian church, the church in Rome, Smyrnaeans and to Polycarp, another disciple of John, has multiple references to the fact of Jesus is God.... for example
To the Ephesians: Ignatius opens his first epistle by telling the Ephesian church it is ". . . united and elect in a true passion, by the will of the Father and of Jesus Christ our GOD" (introduction). He commends them for ". . . having your hearts kindled in THE BLOOD OF GOD" (1:1 compare Acts 20:28).
Next comes a very interesting passage, "There is one only physician, of flesh and of spirit, generate and ingenerate, GOD IN MAN, true Life in death, Son of Mary and Son of God, first passible and then impassible, Jesus Christ our Lord" (7:2).
2. Polycarp (69-155 AD)
Polycarp was alive only 30 years after Jesus walked on the earth. He wrote letters to the churches and was later burned at the stake for his faith. Polycarp in his letter to the church at Phillipi, told them to read what Ignatius had written before hand and then said to them..". . . may He (God the Father) grant unto you a lot with and portion among His saints, and to us with you, and to all that are under heaven, who shall believe on our Lord and GOD Jesus Christ and on His Father that raised Him from the dead
Both of these men were contemporaries of the apostles and they had no hestitation in acknowledging what the early church believed.. that Jesus is God.
Now.. before we move on.. a question!! With such specific references to Jesus being God, why did not the various councils that decided on the specific books to be included in the Canon of Scripture, not include these specific references to Jesus being God, if the Christian Bible and Gospel in particular has been corrupted by those wanting to make Jesus look like God? Wouldn't it have been far easier to just include letters such as these instead of supposedly corrupting obscure passages in the Gospels as they appear now?
3. Justin Martyr lived from 100-166AD. He was martyred by beheading for his faith. Justin Martyr was the first and most respected Christian apologist (defender of the faith) against Paganism ( and particularly worship of a plurality of gods). Doesn't it seem strange, that he who spoke loudest against the worship of many other gods and idols should himself proclaim in his published work "First Apology of Justin Martyr"
that the Church proclaims, ". . . the teachings of the Logos, because he is divine." In reference to the Logos, he writes, "It is only reasonable that we worship him and later he declared , ". . . the Father of the universe has a Son, who--since He is the First-Begotten Logos of God--is true Deity"
Now let's look at some of the later church fathers before the Council of Nicea
4. Melito, bishop of Sardis during the reign of Marcus Aurelius and who died in 190AD, wrote a "homily on the passion" and declared "he rose from the dead as GOD, being by nature GOD AND MAN. This is Jesus Christ, to whom belongs the glory to the ages, Amen."
The fourth century historian Eusibius, lists several books that were written by Melito, and one of these was called "GOD in Bodily Form" (Eusebius p. 186).
5. Iraneaus (120-203 AD)
Iraenaeus was a pupil of Polycarp, who was a disciple of the Apostle John. He wrote a book called "Against False Gnosis". Irenaeus asserts that the Church believes "in one Christ Jesus, our Lord, the Son of God, was incarnate for our salvation". Iranaeus also wrote "So God became Man and the Lord Himself saved us, giving the sign of the Virgin". (Eusibius p 212)
6. Tertullian (160-220AD) was another early and strong defender of the faith in the second century. His major work was called "The Apology". Tertullian wrote at a time when the church was being accused of worshipping a mere human being. This was his response
"We must make, therefore, a remark or two about Christ's divinity."
He continues, "He is the Son of God and is called GOD from unity of substance with God. For God, too, is a Spirit . . . . Thus Christ is Spirit of Spirit and GOD OF GOD . . . . in His birth GOD AND MAN united". Later in the book, he asserts, "Surely Christ has a right to reveal Deity, which was in fact His own essential possession"
In another book "Against Praxes" he said " "this One was sent by the Father into the Virgin, and was born of her, MAN AND GOD, the Son of Man and the Son of God, and called Jesus Christ"
Now.. it's important to understand, that as the original Apostles began to die, the understanding of the Deity of Christ began to be denyed. This teaching was began by a man known as Artemon. A response to his denial of the Lordship of Christ was written in a book written by an unknown author called "The Little Labyrinth" (c 200AD). Eusebius states that that this book shows that "the heresy of the Saviour being only human, is exposed in this book as a recent invention" (Eusebius p 235)
This suggestion might perhaps have been credible if in the first place Holy Scripture had not presented a very different picture; and there are also works published before Victor's time (bishop of Rome 189- 199), written to defend the truth against both pagan criticism and current heresies--I mean by Justin, Miltiades, Tatian, Clement, and many more. In every one of these Christ is spoken of as GOD. For who does not know the books of Irenaeus, Melito, and the rest, which proclaim Christ as GOD AND MAN, and all the psalms and hymns written from the beginning by faithful brethren, which sing of Christ as the Word of God and address Him as GOD? (Eusebius, pp. 235f).
So you see, and I'll enlarge on this later.. the early church only knew Jesus as God.. the heresy of his being only man was first introduced in the early second century. And the end result of this heresy was the coming of a later "prophet".. Muhammed who would introduce another Religion as a result of the spreading of this heresy namely Islam.
"Search, then, and see if the divinity of Christ be true.
If it be of such nature that the acceptance of it transforms
a man, and makes him truly good, there is implied
the duty of renouncing what is opposed to it as false"
(Tertullian).