score:3
Regarding first part of your question that “Trinity" is not used in the Christian Bible: answer to this question tries to give the biblical basis for Trinity,
Regarding your second part of the question, on historical origin of the Doctrine of the Trinity, I have come across the following historical notings of Church fathers.
The apostolic Fathers unanimously taught that the "we" in Gen 1:26, refers to the Trinity:
Similar references are also there form all these apostolic Fathers while they were preaching about the concept of Trinity by quoting Genesis 19:24:
Upvote:3
Your question pre-supposes that, since the word "Trinity" is excluded from the Bible, then the "historical origin of the doctrine of the Trinity" is also excluded from the Bible. However, I would beg to differ.
For example, consider the word "monotheism." It too is excluded from the Bible; you will not find the word "monotheism" written explicitly in the text of the Bible.
"Monotheism" is defined as "the doctrine or belief that there is only one God. The Bible states that "there is one God, and there is no other but Him" (Mark 12:32).
The name of a doctrine does not need to be explicitly stated in scripture as long as the elements which define the doctrine are stated or implied.
The historical origin of the doctrine of the Trinity is the Bible. If you would like to know what the doctrine of the Trinity entails, another dedicated question may be in order.
Upvote:5
The Athanasian Creed, formulated a few hundred years after the death of Jesus, defined the Trinity this way: “The Father is God: the Son is God: and the Holy Ghost is God. And yet they are not three Gods: but one God.”
Many would say that it's origin started with Jesus Christ, however that would conflict what the bible say even about his "own" origin (creation) about him being equal:
Colossians 1:13-15
13. Who hath delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son: 14. In whom we have redemption through his blood, even the forgiveness of sins: 15. Who is the image of the invisible God, the firstborn of every creature: 16. For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him:
No where in the scriptures does it make mention of Trinity.
In its 1999 issue on the Trinity, The Living Pulpit observed: “Sometimes, it seems that everyone assumes that the doctrine of the trinity is standard Christian theological fare,” but it added that it is not “a biblical idea.”
“The doctrine of the trinity . . . is not a product of the earliest Christian period, and we do not find it carefully expressed before the end of the second century.”—Library of Early Christianity—Gods and the One God.
In his book The Church of the First Three Centuries, Dr. Alvan Lamson states that the doctrine of the Trinity “had its origin in a source entirely foreign from that of the Jewish and Christian Scriptures; that it grew up, and was ingrafted on Christianity, through the hands of the Platonizing Fathers.”
Who were these “Platonizing Fathers”? They were apostate clerics who were infatuated with the teachings of pagan Greek philosopher Plato.
The Platonic trinity, itself merely a rearrangement of older trinities dating back to earlier peoples, appears to be the rational philosophic trinity of attributes that gave birth to the three hypostases or divine persons taught by the Christian churches. . . . This Greek philosopher’s [Plato’s] conception of the divine trinity . . . can be found in all the ancient [pagan] religions.”—Nouveau Dictionnaire Universel (Paris, 1865-1870), edited by M. Lachâtre, Vol. 2, p. 1467.
History shows that the ancient civilizations and cultures that believed in a Triad god or gods were: Assyria, Babylon, Egypt, Greece, Rome which all were conquering nations, one after another, could have carried their beliefs into Christianity after Jesus' death - during the time of the Romans and of which historically were Pagans.