What It Is and Why Christians Believe It
by Justin Oswalt–
The Doctrine of the Trinity is a vitally important doctrine of the Christian faith because this doctrine explains in essence who God is and what His nature is like. It is part of what distinguishes Christianity from all other religions, especially other Monotheistic faiths. In examining who God is, and to explain the Trinity, we must go to the Bible to present the case for this belief. The Doctrine of the Trinity can be seen in the Old Testament, but can most fully be understand in the revelation of the New Testament scriptures. It can be broken down in the following premises:
1. There is only one God.
2. God has revealed himself as three distinct persons, the Father, the Son, and the Holy Spirit within the Godhead (Trinity).
3. Each person of the Godhead (Trinity) is fully God, co-equal and co-eternal in essence.