Something that drastically changed my theological development and life was and is Historical Theology; I first engaged with it in my seminary Reformation and Patristic Theology classes. For the first time (at that point), pieces really began to fall into place for me (including my undergrad Bible College experience which didn’t get into, so much, actual historical detail [just generalities]), and it enabled distanciation (critical space) for me in a way that allowed for critical space wherein I was finally able to identify the conceptual and historical forces that had brought me to where I was at that seminal point (i.e. my first exposure to Historical Theology). What good Historical Theology does is primarily engage in descriptive detail; in other words good Historical Theology carefully and slowly attends to reconstructing as accurately as possible how theological ideas formed in various periods and strata of the Christian Tradition. Once this step is taken, then we are able to resource the categories and emphases present in whatever period we are looking at, and bring all of those threads into a constructive framework that helps serves the present purposes of the advancement and articulation of the Gospel. What engaging in Historical Theology also has the capacity for (as I already alluded) is to provide a kind of third party perspective on my (our) own theological approach. In a sense, Historical Theology can marginalize a theological notion or trajectory that I might think is novel; and it can marginalize in a way that helpfully keeps me from going down a path that might in the end be fruitless, and ultimately a real waste of the time I am supposed to be redeeming. So Historical Theology can serve as a regulative control on how and what I research, and more prominently it can give me insight into whether or not I am on a fruitful or dilapidated trajectory.
So Historical Theology is a very important discipline that I think any serious Christian theologian and exegete must attend to. But one danger of Historical Theology is that we forget that God still speaks. We can get so caught up into listening to the past that we can forget that there is a present. So good Historical Theology will, in my view, always give way to Constructive Christian Dogmatic Theology. Which means that we will not only soberly engage with the past, but in this sober engagement we will be doing so with a purpose; the purpose is to listen to the living voice of God as it provides continuous communication from the past into the present. And it is this coming into the present by incorporating the voice of God from the past (so theological remembrance, a very biblical motif) into the present that we are able to constructively join in to the diaology of the voices present in the people of God. In other words, good Historical Theology, while providing necessary perspective and fruitful lines of thought, should never be seen as an end in itself; and that is because good Historical Theology is framed by a doctrine of God that is understood as Triune and lively. And God Himself, in Christ, ought to be the One who sets the stage for how we go about engaging in the conversation of His people the Church.
And so in the end, obviously, my view of Historical Theology is that if it is going to be a fruitful endeavor must be understood from a genuinely Christian frame of reference. Good Historical Theology provides perspective because it is an act of humbling ourselves, and accepting the fact that God has meaningfully (and is) spoken to our brothers and sisters in the past. And since God has meaningfully spoken in the past, this guarantees the integrity of what has been communicated in the past since it is not ultimately contingent upon whatever period God’s voice was spoken in and through; but truly, it is contingent upon the integrity of God’s voice. This is not to deny the various modes, expressions, and periods of history in which this voice was given; but it is to recognize that God has spoken, and we need to listen whenever He speaks.