1 Corinthians 2:12-14
12 Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God.
13 Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual.
14 But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.
The first thing to note is that the Bible is written to those who have a heart for God, it is not a history book rather an account of Gods interactions with man. Consider it a spiritual account rather than a novel of sorts. What makes it alive is the perpetual spiritual unfolding of what God has said.
The Bible is considered a pregnant reading, you can read the same text a number of times and continue to learn new things from something written thousands of years ago, yet for those lead by the Spirit of the Lord, they all come to the same conclusions in the end.
The bible is not meant to be a direct read, otherwise there would be no room for the gifts of the Spirit or faith to be involved. What sets the Bible apart is the operation of these particular gifts that make the Bible’s truths a spiritual experience.
One idea that became popular among Christians around the fourth century was that of a trinity of gods.
It was not, however, a new idea conceived by Christians, for there is much evidence of widespread belief in similar ideas throughout earlier recorded history.
Many scholars believe that the Trinity, as taught by Christians, comes from Plato as suggested in the Timaeus, but the Platonic trinity is itself merely a rearrangement of older trinities dating back to earlier peoples.
In Indian religion there is the Trinitarian group of Brahma, Vishna, and Shiva; in Egyptian religion there is the group of Kneph, Phthas, and Osiris. In Phoenicia the trinity of gods were Ulomus, Ulosuros, and Eliun. In Greece they were Zeus, Poseidon, and Aidoneus.
In Rome they were Jupiter, Neptune, and Pluto. In Babylonia and Assyria they were Anos, lllinos, and Aos. Among Celtic nations they were called Kriosan, Biosena, and Siva, and in Germanic nations they were called Thor, Wodan, and Fricco.
Trinities of gods existed in other cultures as well, including, but not limited to, those of Siberia, Persia, Japan, Scandinavia, and Mexico.
Although the Trinity is characteristic of the Christian religion, it is by no means peculiar to it.
The truth is that the Trinity isn't mentioned in the Bible, not only is it not mentioned, but the doctrine is neither found in the New Testament, nor the Old Testament.
Texts like Genesis 1:26
26 “And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth”.
Does convey the plurality of the Godhead. However, in the New Testament there is no doctrine of the Trinity enunciated ..." but only "deduced from a collocation of passages ...."
The formulation 'one God in three Persons' was not solidly established ... into Christian life prior to the 4th century.... Among the Apostolic Fathers, there has been nothing even remotely approaching such a mentality or perspective.
It is generally acknowledged that Tertullian (ca. A.D. 145-220) either coined the term or was the first to use it with reference to God. The explicit doctrine was formulated in the post-biblical period.
The Emperor Constantine summoned the first General Council of the Church of Niceae, in 325, to settle this dispute and so reunify the Church. It condemned the teaching of Arius and produced a creed which declared that the Son is of one substance with and co-eternal with the Father.
Theodosius I convened the second General Council at Constantinople, in 381, which endorsed his definition of Catholicism, finally condemned Arianism .... and reaffirmed the Nicene Creed.
A further dispute arose between the monk Nestorius, patriarch of Constantinople in 428, and Cyril, patriarch of Alexandria about the two natures in Christ. Rome joined on the side of Alexandria against the pretentious claims of the upstart see of Constantinople. Thus politics entered into the dispute.
Once again the state intervened. The third general council of the Church at Ephesus, in 431, was called by the two emperors, Theodosius II of the East and Valentinian III of the West. It condemned Nestorianism, and Nestorius was exhiled to the Egyptian desert in 435.
At the final session, the Catholic Church in the East and West accepted what is known as the doctrine on the Trinity.
This statement of belief, together with other doctrinal definitions, has since been accepted by Eastern and Western Orthodox, Catholic and Protestant Christians.
The facts prove that the doctrine of the Trinity does not appear in the Bible "nor did Jesus and his followers intend to contradict the Shema in the Old testament: 'Hear, O Israel: The Lord our God is one Lord' (Deuteronomy 6:4).
The doctrine developed gradually over several centuries and through many controversies. By the end of the 4th century the doctrine of the Trinity took substantially the form it has maintained ever since."