Biblical and Systematic Theology: Speaking from Different Premises

The most obvious difference between Biblical Theology and Systematic Theology, as already noted, is that while the former adopts a chronological approach, tracing the history of revelation, Systematic Theology treats the Bible as a finished product in which God has spoken his last word.  

But the two disciplines also differ in their fundamental premises. Biblical Theology finds its starting-point in the diversity and variety of Scripture; Systematic Theology presupposes its underlying unity.

There can be no denying the variety. Not only were the scriptures written at 'sundry times': they were also written in 'diverse ways' (Heb. 1:1). This was partly a function of their long historical time-line. They were written over a period of at least a thousand years and some of the oral and written traditions which they used may well go back a good deal further. They inevitably reflect, then, a wide variety of social, cultural and political settings: and, corresponding to this, a wide variety of forms of revelation.

The result is that instead of a Bible in monochrome we have a Bible of varied landscapes, myriad voices and ever-changing colour: a wide variety of literary genres, ranging from narrative to poetry to law to parables to highly didactic epistles and even to fables (Judges 9:8-15); and, even more important, a wide variety of individual authors each with his own experience, gifts, temperament, vocabulary, favourite concepts, unique style and unique life-setting.

The task of Biblical Theology is to highlight the distinctiveness of the various contributions: for example, the contribution of each era, of each literary genre (including Wisdom and Apocalypse) and of each individual voice. Each contribution must be accepted on its own terms.  No two voices and no two eras have the same priorities or the same preoccupations.  No writer feels bound simply to repeat the phraseology and vocabulary of his predecessors: the apostles did not even feel bound to stick to the terminology of Jesus. None follows his example in calling himself 'the Son of Man', none gives 'the kingdom of God' the prominence it had in the Master's teaching, and even prolific writers like the Apostle Paul make little direct use of key Old Testament concepts such as the covenant. On the contrary, each biblical writer plays his own word-game, with the result that the way that one author uses a word is no guarantee that it will mean exactly the same thing when used by another. John alone calls Christ the Logos, Paul alone uses the antithesis of flesh and spirit, the Writer to the Hebrews alone refers to Christ as a priest, and James alone speaks of being justified by works.  

These variations are a tribute to the fact that in the miracle of inspiration the Holy Spirit neither suppressed nor overrode the human personalities of the authors. Instead, they delivered God's word through the ordinary processes of human composition (even to the extent, probably, of wrestling with writer's block and agonising over the question whether it was really wise in the circumstances to say this at all). Biblical Theology glories in these variations, and the preacher who is conversant with its approach will be careful to identify the precise message which this author and this text bears. He may even, on occasion, draw attention to its limitations, pointing out what it does not say, and making good the omission from later revelation.  

The premise of Systematic Theology, on the other hand, is the unity of Scripture: what the Westminster Confession (1:5) calls 'the consent of all the parts'. This in turn rests on the premise that all Scripture was breathed out by God, and while he may breathe out variety he will not breathe out contradiction. Precisely because Scripture in its entirety is the word of God it is the revelation of one saving will and of one plan of salvation. Systematic Theology assumes this unity, takes the whole of divine revelation as its field, and seeks to collate all that God has told us so far, striving towards the point where it can say to the church, 'This is the whole counsel of God. This is what you are to preach.'

Yet we must never forget the provisionality of what we have to say, because our grasp of divine revelation is always partial and always fallible, and therefore always open to revision. From this point of view Systematic Theologians will always operate with a degree of scepticism towards earlier formulations (and of course contemporary 'original' ones, including our own).  

But we also have to recognise, beyond this, that there remain, and will always remain on this side of the End, things which have not yet been revealed. The premise of all theology is that God knows himself, and his self-knowledge is, of course, exhaustive. He could not, however, impart the same exhaustive knowledge to us. Instead, what happens in revelation is that he shares with us a little of what he knows about himself: but only a little, partly because there are aspects of his being which are beyond our capacity, partly because there are things which he thinks it best should remain  hidden for the present, and partly because revelation is in no hurry.  Neither he nor we are short of days.

Solomon recognised (2 Chronicles 6:18) that 'the heavens, even the highest heavens,' could not contain the glory of God; and he added, 'How much less this temple that I have built!' 

Nor, indeed, can the Scriptures themselves. How much less our creeds and theological formulations! There is a parallel here between Scripture and the extra-Calvinisticum: the doctrine that while the 'fullness of the godhead' dwelt in Christ bodily (sōmatikōs) it could not be confined within that body. He was present and active outside (Latin, extra) his human nature, filling heaven and earth, and actively upholding the universe by the word of his power (Heb. 1:30).   

The underlying principle here was that the finite cannot contain the infinite, and it applies equally to Scripture. While divine truth fills the Bible, it is not confined within the Bible. It is indeed true, in the oft-quoted words of John Robinson, that the Lord has fresh truth to break forth out of his holy word. But he also has fresh truth to add to his word: truth which is not contained in our current Scriptures, but which he will 'break forth' to us progressively throughout eternity. After all, 'No eye has seen, no ear has heard ...' (1 Cor. 2:9).

Assuming, then the unity and (provisional) finality of Scripture, what does Systematic Theology talk about? The short answer is that it talks about exactly the same things as Biblical Theology.  

But surely not in exactly the same way?

Donald Macleod is Professor of Systematic Theology at the Free Church of Scotland College, Edinburgh, Scotland. He is the author of A Faith To Live By (Christian Focus, 1998), The Person of Christ (IVP, 1998) and Christ Crucified (IVP, 2014)