The Bible begins as the universe began . . .
"In the beginning GOD created the heavens and the earth."
It begins in that manner for two reasons. First, the Creation is told by Moses as a corrective to all of the false alternative stories which had arisen in the intervening time. Secondly, to begin with God is to set the path for all succeeding knowledge. The person who does not acknowledge God need not pursue the matter any farther. For, the Bible tells us, "The fool has said in His heart, 'there is no God.'" (Psalms 14 & 53)
God has revealed Himself to us through His word, and later through His Son, Jesus, and finally through His Spirit.
He has revealed Himself to be ONE God in THREE Persons.
It is impossible in human terms to fully understand how this can be. Yet it is so, and any who deny it at this point in time have to be considered outside the realm of Christian belief. With the centuries of debate and ponderings, the searching and weighing of the Scriptures, the result is the absolutely concrete truth of the Trinitarian nature of God.
Even though it is impossible to fully illustrate an infinite God in a two-dimensional diagram, one similar to the type shown here has been most helpful to people for centuries.
By following the Diagram one can quickly see that the ONE GOD is revealed in Three Persons: the Father, the Son, and the Holy Spirit. Each of these three IS God, while at the same time each IS NOT the other.
The Father is God, but He is NOT Jesus.
Jesus IS God, but He is NOT the Father. Yet at the same time Jesus is able to say, "I and the Father are one" without contradiction.
The Holy Spirit IS God, yet He is neither the Father nor the Son.