The Importance of Trinitarian Theology (Part 2)

In Part 1, we discussed how the Trinity is central to the Gospel, revelation, and the Christian life and its evolution. We can summarize it like this (h/t Fred Sanders):

First, Trinitarian theology summarizes the biblical story. 

Second, it articulates the content of divine self-revelation by specifying what has been revealed. 

Third, it orders doctrinal discourse. 

Fourth, it identifies God by the Gospel. 

And fifth, it informs soteriology (i.e., how were are saved). 

In Part 2, we will be defining the Trinity – what it is and what it isn't. 

Dr. James White provides the best definition for the Trinity in his The Forgotten Trinity book, that we are aware of, as it is succinct. 

Within the one Being that is God, there exists eternally three coequal and coeternal persons, namely, the Father, the Son, and the Holy Spirit.

This definition rests on three fundamental truths:

There is only one God, eternal, immutable. (Monotheism)

The Father, the Son, and the Spirit are three eternal Persons. They are not identified with one another but differentiated. (Three persons)

Scriptures identify the Father, the Son, and the Spirit as each fully divine. (Equality of the persons)

Deny one or more of these, and you fall into grave error.

Deny that there is one God, and you become a polytheist.

Deny the three persons, and you make God into a caricature purported by heretics -- e.g., modalism. This heresy claim that a unitarian God has revealed himself in three modes. Well-meaning Christians often become functioning modalists when they use an egg or a clover to "describe" the Trinity. 

Deny the equality of the persons, and you get the heresy of subordinationism. This error states that the Son and Spirit are inferior to the Father. A helpful diagram (re-created below) from Alpha & Omega Ministries’ article, “A Brief Definition of the Trinity,” is a helpful guide.

When describing idolatry, John Calvin wrote, "The human mind, stuffed as it is with presumptuous rashness, dares to imagine a god suited to its own capacity; as it labors under dullness, nay, is sunk in the grossest ignorance, it substitutes vanity and an empty phantom in the place of God." (See Book 1, Chapter 11, Section 8)

We must not make the same mistake even when we have the best of intentions. 

We mention elsewhere, following in stride with J. Gresham Machen, that Christianity is history and doctrine; God reveals himself in word and deed. The Trinity is revealed in the Incarnation as the promise of Redemption is realized. As the Triune God reveals himself, an inner unity binds together divine words and actions. 

R.C. Sproul once said that the Trinity is a valuable shibboleth, as it reveals where a person stands in relationship to orthodox, historical, Biblically-sound, Christian faith. 

Never forget, Christianity is inherently Trinitarian. Remove the Father (the fount of salvation), the Son (the sacrifice for sins), or the Spirit (the comforter and advocate), and you end up with another less-than-unique religion (h/t James White).

To delve deeper into this rich and important doctrine, check out these resources:

The Triune God, by Fred Sanders

The Holy Trinity, by Robert Letham

In Part 3, we will cover some common objections to the doctrine of the Trinity.