As Berkhof explains, if we depart from the specific teachings of Scripture and begin to speculate about the nature of the Trinity, it is very easy to fall into error. If one denies the unified essence of being of the three Persons, it will inevitably lead to tritheism (the belief in three separate and distinct gods). If one denies the reality of the personal distinctions among the three Persons, it will inevitably lead to modalism (the belief that God is a single person who has revealed Himself in three modes or forms). To keep from falling into these errors, and in an effort to be true to the witness of Scripture, orthodox theologians have developed two different ways of speaking about the Trinity.

In our current sermon series in the Gospel According to John, we are in what is often referred to as the “Farewell Discourse” (John 14-17). The first part of John’s Gospel describes Jesus’ public ministry, but in this section Jesus gives a private lecture series, if you will, to His Disciples. Most of this portion of John’s Gospel is not found in in the other Gospels. And, one of the unique elements of this discourse (this extended series of teachings by Jesus) is the emphasis upon the Person of the Holy Spirit.

In the passage for the sermon this coming Sunday in the second half of John 14, Jesus explains some new things about the Person and work of the Holy Spirit; however, this passage is actually about all three Persons of the Godhead: God the Father, God the Son, and God the Holy Spirit. In Jesus’ teaching, we learn that these three Persons do different things and perform different functions in the work of salvation; at the same time, they are one in essence and being.

The Importance of the Doctrine of the Trinity

The doctrine of the Trinity is no minor teaching of the Bible and the Christian faith. It is an essential understanding of all those who claim the name of Christ. Apart from a basic understanding of the Trinity, one cannot know the true Christ as He is offered in the Gospel. And, the doctrine of the Trinity is the main doctrine which sets Christianity apart from all false religions and beliefs. There are several monotheistic religions and even more polytheistic religions, but the witness of the Scripture and the Christian faith is that God is both one and three.

The Mystery of the Doctrine of the Trinity

As we seek to understand the Trinity, we must also confess that this doctrine is a mystery. In our finitude and creatureliness, there are things that we cannot fully comprehend about the nature of God. Louis Berkhof explains:

The Trinity is a mystery, not merely in the Biblical sense that it is a truth, which was formerly hidden, but is now revealed; but in the sense that man cannot comprehend it and make it intelligible. It is intelligible in some of its relations and modes of manifestations, but unintelligible in it is essential nature. The many efforts that were made to explain the mystery were speculate rather than theological. They invariably resulted in the development of tritheistic or modalistic conceptions of God, in the denial of either the unity of the divine essence or the reality of the personal distinctions within the essence. The real difficulty lies in the relation to which the person in the Godhead stand to the divine essence and to one another; and this is a difficulty which the Church cannot remove, but only try to reduce to its proper proportion by a proper definition of terms. It has never tried to explain the mystery of the Trinity, but only sought to formulate the doctrine of the Trinity in such a manner that the errors which endangered it were warded off. (Louis Berkhof, Systematic Theology, p 89).

The Balancing Act in Seeking to Understand of the Doctrine of the Trinity

As Berkhof explains, if we depart from the specific teachings of Scripture and begin to speculate about the nature of the Trinity, it is very easy to fall into error. If one denies the unified essence of being of the three Persons, it will inevitably lead to tritheism (the belief in three separate and distinct gods). If one denies the reality of the personal distinctions among the three Persons, it will inevitably lead to modalism (the belief that God is a single person who has revealed Himself in three modes or forms).

To keep from falling into these errors, and in an effort to be true to the witness of Scripture, orthodox theologians have developed two different ways of speaking about the Trinity.

(1) The Ontological Trinity

To speak in terms of the ontological Trinity, we are describing what God is. ‘Ontological’ means ‘relating to being or existence.’ So, in speaking about the ontological Trinity, we describe the unity and equal divinity of each of the Persons of the Godhead in their essence or being. All three Persons, the Father, the Son, and the Holy Spirit, are infinite, eternal, immutable (unchangeable), omnipotent (all powerful), omniscient (all knowing), omnipresent (everywhere present), holy, just, and good.

(2) The Economic Trinity

To speak in terms of the economic Trinity, we are describing what God does. ‘Economic’ isn’t used here to describe finances or trade, but in the older sense of ‘relating to the arrangement of activities.’ So, in speaking about the economic Trinity, we describe the different activities which are ascribed to each of the Persons of the Trinity. These different activities are reflected in the historic creeds of the church (e.g., the Apostles’ and Nicene Creeds).

God the Father is neither begotten by, nor proceeds from any other Person; He is the maker of all things. God the Son is eternally begotten of the Father; for our salvation, He was made man, suffered, was crucified, buried, rose again from the dead, ascended into heaven, is seated at the right hand of the Father, and will come again. God the Holy Spirit proceeds from the Father and the Son from all eternity; He is the Lord and giver of life, spoke through the prophets, and guides God’s people into all truth.

A Good Summary of the Doctrine of the Trinity

These ways of speaking of the three Persons of the Trinity – as ontological and economic – maintain the true witness of Scripture and keep us from falling into error through speculation. Questions 6-11 of the Westminster Larger Catechism give a biblical definition of the doctrine of the Trinity that maintains this important balance:

WLC 6. What do the scriptures make known of God?
A. The scriptures make known what God is, the persons of the Godhead, his decrees, and the execution of his decrees.

WLC 7. What is God?
A. God is a Spirit, in and of himself infinite in being, glory, blessedness, and perfection; all-sufficient, eternal, unchangeable, incomprehensible, every where present, almighty, knowing all things, most wise, most holy, most just, most merciful and gracious, long-suffering, and abundant in goodness and truth.

WLC 8. Are there more Gods than one?
A. There is but one only, the living and true God.

WLC 9. How many persons are there in the Godhead?
A. There be three persons in the Godhead, the Father, the Son, and the Holy Ghost; and these three are one true, eternal God, the same in substance, equal in power and glory; although distinguished by their personal properties.

WLC 10. What are the personal properties of the three persons in the Godhead?
A. It is proper to the Father to beget the Son, and to the Son to be begotten of the Father, and to the Holy Ghost to proceed from the Father and the Son from all eternity.

WLC 11. How doth it appear that the Son and the Holy Ghost are God equal with the Father?
A. The scriptures manifest that the Son and the Holy Ghost are God equal with the Father, ascribing unto them such names, attributes, works, and worship, as are proper to God only.

In our sermon this coming Sunday, we will examine not only the doctrine of the Trinity, but how the life of the believer is wrapped up in the inter-relational life of the Father, the Son, and the Holy Spirit.

And now, to those “who are chosen according to the foreknowledge of God the Father, by the sanctifying work of the Spirit, to obey Jesus Christ and be sprinkled with His blood: May grace and peace be yours in the fullest measure!” (1 Peter 1:1-2)

Peter M. Dietsch is pastor of Providence PCA in Midland, Texas. This article first appeared on his church website and is used with permission.

[Editor’s note: One or more original URLs (links) referenced in this article are no longer valid; those links have been removed.]