(A fragment from the 13 November 1968 meeting of the Concordia Seminary Department of Systematic Theology)
….What is most “systematic” about systematic theology is, not merely that it arranges its material – say, the biblical data – in this or that orderly way, (that much is true of all the theological disciplines) but rather that it consciously and explicitly insists on asking “Why.” It asks for The Sufficient Reason, The Adequate Basis, The Fons, never resting until it has found “Reason Enough.” Why, for what reason finally, is this or that Christian claim made? By saying that the systematician asks for the “why,” I am not suggesting that he does not know what it is. On the contrary, because he does know, at least in principle, what that sufficient reason is, his asking is meant chiefly to ask it into clarity, into the full prominence it deserves. He cannot even settle for the explanation, “Why, because Scripture says so.” He still persists and asks again, “And why, in turn, does Scripture say so?” His job is done only when he has traced the reason back to The Source: namely, God’s reconciling the world unto himself in Christ Jesus – in other words, the gospel. The systematician’s task is to “necessitate” Christ.
His task is properly to distinguish law from promise. But this distinguishing is not an end in itself. Law and promise need distinguishing so that they can be restored to the original relationship in which they already operate within scripture. The trouble is that men come to that biblical law-promise relationship prejudiced by a perennial Vorverstandnis (opinio legis), and thus re-combine law and promise unbiblically, with the resultant loss of both, law and promise. The systematician disentangles this mis-meshing, does his distinguishing, so that he can restore law and promise to their original biblical –i.e, evangelical – order….
Robert W. Bertram