There is a great deal of discussion happening among Evangelicals, and others beyond Evangelicalism, about the doctrine of the Trinity for three important reasons.
First, the doctrine of the Trinity is at the heart of the Christian faith. Remove the doctrine and you no longer have Christianity. It is at the heart of God. This doctrine is also at the heart of salvation. It is absolutely critical and essential.
Second, there are some that are suggesting/recommending tweaks or edits to the doctrine of the Trinity. Though it is always good to think and rethink doctrinal truth in each age, not only to reaffirm the teaching but also to refine in appropriate ways in light of a new day.
Third, the spread of Islam, in which the Trinity is denied, has resulted in this doctrine becoming more prominent and pronounced in a defense of the Christian faith with Muslims.
This changing landscape has revealed that Evangelicals need to do much better in their Trinitarian theology. The doctrine is often not known or understood well, biblically, theologically or historically.
David F. Wells, Distinguished Senior Research Professor at Gordon-Conwell Theological Seminary, who prior to this post he taught at TEDS and chaired its division of systematic theology, has written a new book on the doctrine of the Trinity, What is the Trinity? (Phillipsburg: P & R, 2012), in the Basics of the Faith series. This an excellent series that consists of brief treatments, more like booklets, yet without being simple or simplistic. This book consists of 38 pages.
Wells introduces the booklet in this way:
This much is certain. Had the Christian faith merely been a human invention, Christians would never have come up with the doctrine of the Trinity. This doctrine is too thorny to understand and too difficult to explain for anyone to have deliberately fabricated it. There is no other religion that has anything remotely like this. No, this is not the fruit of our imagination but a doctrine of the way things are. God is triune. Knowing him in his triunity is central to Christian faith. Indeed, without this truth, that faith is not Christian at all.
Given this doctrine’s centrality, it may seem surprising that there is no single verse in the Bible, or even a single passage, that explains how it is that God can be one in being and yet have three centers of self-consciousness within his being: the Father, the Son, and the Holy Spirit. Why is this?
The teaching that God is triune has to be constructed from many passages for two main reasons. First, there are many facets to it. It is not a simple doctrine. Second, God’s disclosure of himself did not take place all at once. He revealed his triune nature only gradually and across large stretches of time. It is therefore revealed across a large swath of Scripture.
Wells then sets the direction for the rest of this articulation:
What we need to do first is to see how God’s own self-disclosure unfolded across time. Here we are thinking about biblical teaching. We begin with the truth that God is one. Following that, we will see how the distinctions between Father, Son, and Holy Spirit were established and developed. We then need, second, to think historically about how the early church helped us to understand these truths. We will conclude by thinking about some of the practical connections that flow from the biblical doctrine of the Trinity.
In the rest of the book, Wells addresses these key truths about the doctrine of the Trinity: God is One; God is Tripersonal; The Trinity Defined; Connections to Practice: The Gospel, i.e. evangelism, and Prayer.
I would encourage you to buy the book and read it. Once you have completed it, have the elders and other leaders of the local church read and discuss it. Because of its brevity, it is doable. And it is important!