Is the Old Testament showing eternal truths, or truths that were true only for that time, or showing that it was true that those things were presented as truths - whether or not they actually were truths? In these questions lurk both a slippery slope toward the heresy of Marcionism, and another slippery slope toward a woodenly dogmatic and hyper-literal reading of the text.
Phrased another way, one can ask if the faith of the Old Testament is the faith of the New Testament. Or is it a separate faith? Exploring this question, Otto Eissfeldt writes:
The tension between absolute and relative, between transcendence and immanence, is the current problem of theology. For biblical scholarship, this general problem is reduced to a particular one: history and revelation. It is with this problem that the study of both Testaments, of the New just as of the Old, has to grapple, and a new solution must be found that applies fundamentally to both. However, particular matters in the Old Testament differ from those in the New, so that a treatment restricted to the Old Testament is legitimate. The question, then, is whether the religion of the Old Testament is to be understood and presented as a historical entity like other religions of antiquity, and thus in terms of the history of Israelite-Jewish religion, or as a religion which is, even if in some limited way, the true religion, the revelation of God, and thus - so the term will be understood here - as “Old Testament theology.”
So there are two approaches. The first approach looks at the text as a source regarding the history of religion: What did people believe? What were the doctrines and practices? Did that belief change or develop over time? The second approach sees the text as a source of theological truth: Which spiritual insights can the reading find in the Old Testament? How does God reveal Himself in the text?
Obviously and fittingly, the historical approach tends to use past tense verbs, while the theological approach tends to use present tense verbs.
The two approaches certainly interact with each other. Can they be harmonized? Otto Eissfeldt suggests that, finally, they can even be united:
Despite every distinction between the two approaches, the historical and the theological, it is nonetheless finally the case that, seen from a higher vantage point, they form a unity - and they do so not just to the extent that its importance to us as the source of revelation, rather than only or even primarily as the object of historical knowledge, accounts for the extraordinarily urgent historical investigation of Old Testament religion. Rather, beyond all this, we are confident that it is the one identical truth for which knowledge strives and by which faith is grasped. Knowing and believing belong, as we have seen, to two parallel planes, and they must meet each other in infinity - but only in infinity. Within the finite realm the two approaches form a unity only to the extent that one person can master them.
Eissfeldt seems, perhaps, to suggest that the wisest course is to pursue both approaches, and to strive to discover the organic unity of which each displays an aspect.
