Hasel: biblical theology as a "reciprocal relationship" between the Testaments

"Biblical theology...must maintain its place as the crown of biblical studies. It must maintain its intimate connection with OT and NT theology...

"Biblical Theology must integrate OT and NT theology in a dynamic way that overcomes the present juxtaposition of OT and NT theology. This can be creatively accomplished once biblical theology recognizes as its boundaries the full biblical canon and deals with the biblical texts in the final form in which they meet the eye. Since the two testaments produce *one* Bible, it is difficult to look at OT theology in a totally isolated way 'as if the New Testament did not exist'. Likewise, a NT theology can hardly be produced as if the OT did not exist.

"W. Eichrodt has observed correctly that there is a 'historical movement from the Old Testament to the New [and] there is a current of life flowing in reverse direction from the New Testament to the Old. This reverse relationship also elucidates the full significance of the realm of OT thought.' Only where this reciprocal relationship between the testaments is understood and reflected do we find the correct place and definition of biblical theology. Biblical theology must be open to the full biblical context..." -- Gerhard Hasel, "The Future of Biblical Theology" in "Perspectives on Evangelical Theology", ed. Kantzer and Gundry