When we say that the Bible is ‘the Word of God’, what we are actually claiming about it? It is to answer this question, which is both theological and also deeply practical and vital, that the branch of theology called ‘the doctrine of Scripture’ has been developed.
The best place to start is with what the Bible says about itself, and about how God uses language. From the very beginning, God shows himself to be a God who speaks. More than that, it is by means of his words that he acts. Thus in Genesis ch.1 for God to say “Let there be light”, and for God to create light, are one and the same thing. This fundamental characteristic of God continues through the Bible. The primary means by which God establishes a relationship with humanity is through his covenant (see for example Gen. chs. 15 & 17). A covenant is at heart a promise, and a promise simply cannot meaningfully be made without speaking. That God has chosen to relate to us in this way leads to a significant fact: when we encounter the words which God speaks, we are encountering God-in-action. Thus when Abraham (in fact still as Abram) hears the words of God’s promise and trusts them (Gen. 12.1-9), he thereby encounters God and enters into a relationship with him. Right through the Old Testament, to speak of ‘the word of God’ is often in effect another way of speaking of God at work in such a way that he makes himself known to his people (see for example Isa. 55.10-11).
When we come to the New Testament, we discover that Jesus Christ is ‘the Word’ (John 1.1; 1 John 1.1), who fulfils in himself everything which the Old Testament language of ‘the word of God’ had been pointing to. Anyone who saw Christ at work and heard him speak had seen God in action and had heard God, because Jesus spoke only what the Father had given him to say. Yet Christ also taught his followers two crucial things. First, he made clear that he would continue to give the apostles, beyond his ascension, words that came directly from him, coming to them through the Holy Spirit (John 16.12-15). In this key passage Jesus sets out the basis on which the writings of the apostles, which form our New Testament, would come to be regarded as ‘Scripture’, that is, as God’s own words, in the same way as the Old Testament (note Peter’s incidental reference to Paul’s writings in this regard, 2 Peter 3.16). Second, Jesus made clear that the words which his apostles would speak faithfully about him would continue to be the means by which people would encounter him in action (Matt. 10.14-15, 40). Thus, when someone hears the apostolic message of Jesus, which for us has been set down in Scripture, they are encountering Jesus Christ coming to them spiritually to present himself to them as Saviour and Lord.
It is this rich biblical picture which is summed up in the well-known verse, 2 Timothy 3.16: ‘All Scripture is God-breathed’. The single Greek word translated ‘God-breathed’ (theopneustos) here says, no more and no less, that what the Bible says (of course properly interpreted historically, and in light of the whole of Scripture) is also what God says.
This brief biblical outline makes clear that Scripture is not simply a book about God. It is instead the very means by which God chooses to come to create and sustain his covenant-relationship with us, in the power of the Holy Spirit. We can only properly describe what the Bible is, then, if we describe what God uses the Bible to do as part of his action in this world.
A helpful way to do this theologically is to think of the particular relationship which each member of the Trinity has to the Bible.
Thinking of God the Father, the Bible is his covenant-book. That is, the Bible as a whole is the form in which the Father comes to us to repeat for us the promise to be our God, and to save fully on the Last Day all who have repented and trusted in Christ. Historical research has shown that the book of Deuteronomy is structured in a pattern very similar to covenant-treaties which kings of that time drew up with nations who were subject to them. Yet the description of ‘covenant-book’ also fits well with the nature of the Bible as a whole. It contains laws which stipulate how the covenant-people should live, in order to remain faithful to the Lord. It contains apocalyptic writing, in which the full consequences of our response to the covenant, whether it be to trust God or to reject him, are laid bare. And it contains narrative (i.e. Gospel and history), in which God’s faithfulness to his covenant, and the consequences of human obedience and disobedience, are shown in action in numerous different situations. Indeed, once we think of the Bible in these terms, it is not a surprise to find that narrative is the most common form of writing in the Bible, because it is especially narrative that can dramatically answer the questions we most often want to ask when faced with someone making a promise to us: ‘Are you trustworthy? On what basis can I confidently trust you? And what will happen if I won’t trust you?’. Through narrative, and through the whole of Scripture, the Father comes to us, demonstrating himself to be trustworthy.