The doctrine of the Trinity states that “the Father is God, the Son is God, and the Holy Spirit is God, and yet there are not three gods but one God.” In other words, 1+1+1=One! When it comes to explaining how this can be, our best theologians cannot explain it. It is declared as a mystery that cannot be explained and so we are told to just accept it.
The Trinity doctrine was not formalized until long after the Bible was completed and the apostles were long dead in their graves, and long after the man who introduced the word Trinity was dead and in his grave. It took later theologians centuries to sort out what they believed and to formulate the belief in the Trinity!
The New Bible Dictionary says that “the formal doctrine of the Trinity was the result of several inadequate attempts to explain who and what the Christian God really is ... To deal with these problems the Church Fathers met in [A.D.] 325 at the Council of Nicaea to set out an orthodox biblical definition concerning the divine identity.” However, it wasn't until 381, “at the Council of Constantinople, [that] the divinity of the Spirit was affirmed.”
By no means are theologians' explanations of the Trinity doctrine clear. Religious writer A.W. Tozer in his book The Knowledge of the Holy states that the Trinity is an “incomprehensible mystery” and that attempts to understand it “must remain forever futile.” He admits that Churches, “without pretending to understand,” have nevertheless continued to teach this doctrine (1961, pp. 17, 18) He then remarkably concludes, “The fact that it cannot be satisfactorily explained, instead of being against it, is in its favor.” — (p. 23)
The New Unger's Bible Dictionary in its article on the Trinity concedes that the Trinitarian concept is humanly incomprehensible, “It is admitted by all who thoughtfully deal with this subject that the Scripture revelation here leads us into the presence of a deep mystery; and that all human attempts at expression are of necessity imperfect.” — (1988, p. 1308)
Cyril Richardson, professor of Church history at New York's Union Theological Seminary, though a dedicated Trinitarian himself said this in his book, “My conclusion, then, about the doctrine of the Trinity is that it is an artificial construct ... It produces confusion rather than clarification; and while the problems with which it deals are real ones, the solutions it offers are not illuminating. It has posed for many Christians dark and mysterious statements, which are ultimately meaningless, because it does not sufficiently discriminate in its use of terms.” — (The Doctrine of The Trinity, 1958, pp. 148-149)
He also admitted, “Much of the defense of the Trinity as a 'revealed' doctrine, is really an evasion of the objections that can be brought against it.” — (p. 16)
A Dictionary of Religious Knowledge states regarding the Trinity, “Precisely what that doctrine is, or rather precisely how it is to be explained, Trinitarians are not agreed among themselves.” — (Lyman Abbott, editor, 1885, “Trinitarians”)
Why do even those who believe in the Trinity doctrine find it so difficult to explain?
The answer is simple yet shocking. It is because the Bible does not teach it! One cannot prove or explain something from the Bible that is not Biblical. The Bible is our only reliable source of divine revelation. And the truth as we will see is that the Trinity concept simply is not part of God's revelation to mankind. It is a doctrine of devils to steal souls from the kingdom.