“What must be in order for what is to be what it is?” is a question which provides a solid method by which one can discover the truth. That's how the biblical authors began—with the a priori of God as the Origin of truth, justice, meaning, morals and beauty. And that's exactly where you find proof of the trinity.
So just how do you apply this method to the doctrine of the Trinity? Well you begin with the Trinity as an a priori concept, then Ask yourself, if the Trinity is true, what kinds of things should I expect to find in the Bible? Then, if you go to the Bible and do in fact find those very things which “must be” in order for the Trinity “to be what it is,” then we have all the proof we need that the Trinity doctrine is true.
The only alternative is to begin with the a priori assumption that the Trinity is not true. While we can understand why the non-Christian would want to begin with this as his a priori, why would a professing Christian want to start there as well? To begin with unbelief is to lose the battle before its starts. And if that's the case no amount of proof is going to convince you otherwise.
I and the Father are one John 10:30
One sentence definition of the trinity.
"The Trinity is the foundational Christian belief that God is one Being who exists in three Persons.”
The word
Trinity means
three-in-one. No, the word
Trinity does not appear in the Bible. But that doesn’t mean the concept isn’t clearly taught. The early church absolutely believed – and taught – the belief in a God who was three-in-one.
The Bible is full of Scripture speaking of there being only one God (see
Deuteronomy 6:4 for starters), as well as the Father, Son, and Holy Spirit all being God. That’s where the confusion comes from. I won’t go into all of the verses here (simply type “bible verses about the Trinity” into Google and you’ll find plenty).
Before moving on to
understanding the idea of one Being existing in three Persons, I will point out that the
Biblical idea of the Trinity goes all the way back to the first verse in the first chapter in the first book of the Bible.
Genesis 1:1 says this:
The Hebrew word for God is
Elohim. The verb for created is
bara. Elohim is the plural form of the word God. However,
bara is the singular conjugation of the verb. Every time the word
Elohim (plural) is used throughout the Old Testament referring to the one, true God, it is used with a singular conjugation of the verb. The idea that God is somehow three and one starts on
Page 1 and never changes.