The Trinity (LatinTrinitas,lit. 'triad') is the doctrine almost universlly accepted by Christians, that holds that:

  • The Father, the Son and the Holy Spirit are One God (not three Gods)

  • The Father, the Son and the Holy Spirit are equal in power and glory, and the same in essence.

  • The Father functionally is superior to the Son and the Holy Spirit (both Son and the Spirit are obedient to the Father)

  

 

We know the early Christians did not believe in a trinity because:

First, the original Jesus-following movement was still very Jewish and as such was not very interested in doctrines per se. What really concerned first-century Jews was not so much the details of correct beliefs, but rather Jesus, his life and mission.

Second, there was no Holy Spirit: While some pre-Jesus Jews believed in the notion of “the Son of Man” as an eternal heavenly being whom God would one day seat on the throne of His glory. Some Jews, even prior to Jesus, thought of the relation between God and his Word in nearly identical terms as does John’s Gospel (John 1:1). But there was never a third party!

Third,  there is  little about the divinity of the Holy Spirit in the New Testament as Jsus is said to be conceived of him. But the Apostles gave no personality characteristic to the Holy Spirit and seemed to regard him as merely a divine emanation flowing from the Father and the Son (as in Jehovah Witnesses’ theology)

for further information about this belief:

Associated Bible Students refute the Trinity

The Lost Doctrines of Christianity

Understanding the Scriptures as Taught by the Apostles

The Truth about the Trinity

Facts on the World's Religions

The doctrine of the Trinity as such is not found in the Bible. It is systematized from various Biblical texts by later Christians to present one coherent and accurate teaching that attempts by the Emperor Constantine to unify all believers.  The ancient Romans saw Greek as a beautiful and romantic language - much as modern Americans view French..  It is said that during an early church council presided by Constantine - the Emperor heard the word homoousios spoken in one of the debates and found the word so beautiful he immediately declared it to be a doctrine to be adopted by the church

The confusion over the doctrine no doubt has arisen from the interpretation of the word person.  In the modern world, the word person means an individual being.  But in ancient Greek, a persona was the mask worn by an actor.  In other words, the doctrine is saying God wears three masks, Father, Son and Holy Ghost, but he is just one being.

As it stands now the Trinity is a being who exists, simultaneously and eternally, as a mutual indwelling of three personalities the Father, the Son (incarnated as Jesus)  and the Holy Spirit.  Since the 4th century, in both Eastern and Western Christianity, this doctrine has been stated as "three persons in one God," all three of whom, as distinct and co-eternal beings, are of one indivisible Divine essence.  The doctrine also teaches that the Son himself has two distinct natures, one fully divine and the other fully human, united in a  hypostatic union.  Support of the doctrine of the Trinity is known as Trinitarianism. Most denominations within Christianity are Trinitarian, and regard belief in the Trinity as a mark of Christian orthodoxy.

Non Trinitarian Christians

By far the three largest nontrinitarian Christian denominations are The Church of Jesus Christ of Latter-day Saints ("Mormons"), Jehovah's Witnesses 
and the Iglesia Ni Cristo, though there are a number of other smaller groups, including \Christadelphians,\Christian Scientists,\Dawn Bible Students,\Living Church of God,\Oneness Pentecostals,\Members Church of God International,\Unitarian Universalist Christians,The Way International,The Church of God International and theUnited Church of God.


Nontrinitarian views differ widely on the nature of Jesus, and the Holy Spirit. Various nontrinitarian philosophies, such as Adoptionism, Monarchianism, and Subordinationism existed prior to the establishment of the Trinity doctrine in AD 325, 381, and 431, at the Councils of Constantinople, and Ephesus.  Nontrinitarianism was later renewed by the Cathars in the 11th through 13th centuries, in the Unitarian movement during the Protestant Reformation, in the Age of Enlightenmentof the 18th century, and in some groups arising during the Second Great Awakening of the 19th century.


The Christian doctrine of the Trinity is not present in the other major Abrahamic religions.


An Abrahamic religion is a religion whose followers believe in prophet Abraham and his descendants to hold an important role in human spiritual development. The best known Abrahamic religions are Judaism, Christianity and Islam. Smaller religious traditions sometimes included as Abrahamic religions are Samaritanism, Druze, Rastafari, Yazidi, Babism, Bahá'í Faith.