I find that the Trinity is one of those difficult doctrines to explain and to source. As Fred Sanders pointed out in his article Think Bigger in Biola Magazine, there really is not a “Trinity Verse”:
…I would prefer to have a doctrine be stated clearly and concisely in one place. I like my doctrines verse-sized. I sometimes wish there were one verse that said, “God is one being in three persons, Father, Son and Holy Spirit.”But unfortunately the single slam-dunk case closed verse does not exist. So the question remains, is the Trinity Biblical? While Sanders’ piece is not a comprehensive handling of (there has been, and to a lesser extent remains, quite a bit of debate over what all should be included in) the doctrine of the Trinity, he does a good job of showing how the doctrine can be built in shorter passages. This is one of those doctrines that I touched on in my Credo Paper (See my posting The Intersection of Revelation and Apple Pie for an introduction to my Credo Paper) where my head-knowledge and foot-knowledge diverge a bit. Although in this case it is different. I touched on how I know having a personal God does not always affect how I act but this disconnect is different. In my Credo I state:
All of God’s attributes exist within each member of the Trinity. God is of one fundamental nature that exists in three persons: the Father, the Son and the Holy Spirit. Each member of the Trinity is a distinct person from the other but is of the same substance. This one fundamental nature, or essence, is also called the Godhead. The Godhead’s separate persons: the Father, the Son and the Holy Spirit all operate in unity with one another (John 14:10-11, 15:26, 16:13-15). Each person of the Trinity being of the same substance means that each member is Divine and therefore worthy of worship.This doctrine does not always translate into foot-knowledge simply because it can be so difficult to wrap my head around. I get that each member of the Trinity is of the same substance. I get that each member of the Trinity is distinct and separate from each other. I get that each member of the Trinity together make up what is called the Godhead and together they are one God. I get that all works together at the same time but I do not understand how.
The doctrine of the Trinity should have a very real impact on my life. Because of the Holy Spirit lives within me, I can have the peace of God through Jesus Christ even when the world is going to pieces around me. I have to admit that I must put the word “can” in the previous sentence. It should be “do” but I do not always have “do”.
It should also have a very real impact on my worship of God. Yet there are times that I simply focus on one person of the Trinity. I think that it happens because I tend to have a modal view of the functions of God. I see God the Father doing one thing, God the Son Jesus Christ doing something different and God the Spirit doing something completely different. What I need to try and move from head-knowledge to foot-knowledge is that all three persons of the Trinity are working together in order to accomplish the same thing.
For further reading on the Trinity:
Bob Passantino has a good apologetic article called Is The Creedal Doctrine of the Trinity Biblical?
And Greg Koukl at Stand To Reason (one of my favorite resources) has a couple of good articles: The Trinity is Biblical and Does the Trinity Make Sense.