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The Fundamental Doctrine of the Christian Faith

Category Articles
Date July 24, 2023

What would you say is the fundamental doctrine of the Christian Faith? For many of us, the instinctive answer would be, ‘justification by faith alone, in Christ alone’. There is no doubt, or should be no doubt, that this is a biblical and evangelical fundamental. Didn’t Martin Luther describe justification by faith alone, in Christ alone, as ‘The article of a standing or falling church’! We surely understand what Luther is saying. Could anything be more important than knowing how God brings judgment-deserving sinners into a right and reconciled relationship with himself?

Equally surely, however, we cannot say that justification by faith alone is the fundamental doctrine of the Christian Faith. That honour rightly and surely belongs to the doctrine of the Trinity. God himself is the fundamental truth of the Christian Faith. He is Truth itself. He is the Creator, Sustainer, Initiator and Sovereign Lord of all that is. God does not exist for us, we exist for him. Paul’s declaration in Romans 11:36 wonderfully makes the point: ‘For from him and through him and to him are all things. To him be the glory for ever! Amen.’

The pre-eminence of God’s Triune being is heralded in a number of ways in the Scriptures. In Genesis l we see the Triune God in creation: God, his Word, and his Spirit, together bringing into being worlds and star systems out of nothing, and creating man and woman in their own image. Who we are is a personal and visual reminder to us every moment of our existence, of the priority of the Triune God. It is surely not without significance, to say no more, that God should disclose the Triunity of his being to us in the Bible’s opening chapter. All that is has its being from, and is a reflection of the Triune God. In the New Testament, we see the Triune God working in harmony to effect the salvation of sinners: The Father purposing, the Son saving and the Spirit applying (though all actively at work at every moment and at every phase of redemption). Our salvation flows from and owes everything to the eternal fellowship of Father, Son and Holy Spirit. The writer to the Hebrews wonderfully highlights the trinitarian quality and character of Christian salvation when he speaks of Christ offering himself through the eternal Spirit to God (Heb. 9:14). Further, we see our Lord Jesus in John 17:21, praying that his church will be patterned after the harmony and inter-dependent unity of the Trinity. God’s Triunity, his essential harmony and ‘inter-penetratedness’, is what the church is to be modelled on. If nothing else, living more consciously of God’s essential disclosure as Triune, will in some measure (surely!), compel us to ‘make every effort to keep the unity of the Spirit through the bond of peace’ – which is precisely Paul’s argument in Ephesians 4:3-6. We could go on at length, showing how the truth of the Trinity is woven into the very fabric of biblical revelation, of Christian salvation, of the church’s life, and of the individual believer’s growth in grace.

And yet, is it not true that Bible-believing Christians, in general, think so little about the Trinity? Is it not a fact, deeply to be lamented, that our lives are so little framed by this most fundamental of all biblical truths? The opening verses of John’s Gospel introduce to us the unspeakably glorious reality of God’s Triune being, and to its unfathomableness. Before all worlds existed, before anything was, God was! And staggeringly, he was a community, a fellowship: ‘and the Word was with (“face to face with”) God’! The Father was with the Son, and the Son was with the Father. And together they were with the Holy Spirit. ‘In the beginning’, an eternal fellowship of holy love and loving holiness ‘was’. We ‘become’, the Trinity ‘was’. Here, if anywhere, we are on holy ground. We speak, only so that we may not be silent (to quote Augustine)! Here we are quite out of our depth. But yet it is precisely here, that we cultivate that humility of mind that keeps us from becoming insufferably proud in our knowledge of God. Here, if anywhere, we are cut down to size.

John Calvin tells us (Institutes 1.13.17) of a passage in the writings of Gregory Nazianzen that ‘vastly delights me’: ‘No sooner do I conceive of the One than I am illumined by the splendour of the Three; no sooner do I distinguish them than I am carried back to the One. When I think of any one of the Three I think of him as the whole, and my eyes are filled, and the greater part of what I am thinking escapes me’. Can you relate in any way to Gregory or Calvin? Does the truth of the Holy Trinity ‘vastly delight’ you?

What time do we give to pondering the revealed glory of our Triune, Saviour God? What honour do we ascribe, in our personal and corporate worship as the church, to the Persons, beings and actings of our Triune God? The Christian faith rests upon and centres in the Triune God: ‘For from him and through him and to him are all things. To him be the glory for ever! Amen.’


Ian Hamilton is Associate Minister at Smithton Church, Inverness, and President of Westminster Presbyterian Theological Seminary, Newcastle-Upon-Tyne.

This article first appeared first appeared on this website on May 4th, 2012.

Featured Photo by Sebastien Gabriel on Unsplash

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