“Systematic theology is a fence that guards our exegesis from error. If our systematic theology actually comes from the organic unfolding progressive nature of Scripture, then it will not be a straight-jacket, but rather the fence that keeps the children from going out into the dangerous road. Operating without a systematic theology is actually impossible, since the human mind cannot avoid synthesizing what it knows into a coherent whole.”

Theology is like an electric drill. The motor that runs theology is the Bible, the principium (the first principle). It underlies all the theological disciplines, just as the motor runs the drill. In considering a drill, nothing at all will work without the motor. In theology, we explore the meaning of Scriptures in exegesis. We explore what the church has said about the meaning of Scripture in church history (i.e., looking at God’s gifts of the Holy Spirit’s understanding and instruction given to teachers and preachers throughout the church’s history). We look at what the Scriptures say as a whole in systematic theology. We look at how the Scriptures apply to us in practical theology. We examine how we can remove obstacles (by God’s help) to an unbeliever’s coming to faith in God through the Bible in apologetics. What unites all the theological disciplines is the Bible. It is the motor of the drill.

To get the full use out of a drill, it is necessary to know how the parts work, and what all the switches and gears do. Knowing this about a drill is analogous to the exegetical enterprise. Or, to switch metaphors for a moment, exegesis looks at the individual trees in the forest.

Knowing something about the drill’s history can help us appreciate all that a modern drill can do. Hand drills, for instance, while having a charm of their own, and having the advantage of less noise, are also quite a bit (if you’ll pardon the pun) less efficient. This is similar to the function of church history. Studying church history helps us understand how and why we got where we are today. It helps us avoid the mistakes of the past, while also learning from the past so that the past can correct us where we are wrong (we need to make sure we avoid chronological snobbery here).

It is, of course, necessary to understand what a drill does as a whole if we are going to make any use of it. A drill makes holes in wood or some other substance. If we don’t understand its purpose, we might as well forget about using it as a tool, or we might be tempted to use it as a hammer. Understanding what a drill does in its entirety is similar to the project of systematic theology, which always has an eye on the other disciplines, learning from them, and informing them (not to mention guarding the other disciplines from error!).

This last named function of systematic theology needs defense, since most exegetes these days don’t particular like the idea of systematic theology having any role to play in exegesis (and some of them actively despise systematic theology). Systematic theology is a fence that guards our exegesis from error. If our systematic theology actually comes from the organic unfolding progressive nature of Scripture, then it will not be a straight-jacket, but rather the fence that keeps the children from going out into the dangerous road. Operating without a systematic theology is actually impossible, since the human mind cannot avoid synthesizing what it knows into a coherent whole. People who deny that they have a systematic theology actually very much have a systematic theology. It’s usually a very bad systematic theology, since the proponent of it tries to deny that it is even there.

Apologetics doesn’t fit the analogy of a drill quite as well as the other disciplines (and every analogy has its limitations), but I’ll take a stab at it anyway. If someone comes along and doesn’t believe that drill does what a drill actually does, then apologetics is the task of pointing out the various features of a drill that point (again, pardon the pun) towards its actual function.

Lastly, practical theology is like the drill bit. Practical theology is where we answer the question, “so what?” The drill bit is where the drill actually makes a penetrating difference to a piece of wood. If there is no drill bit (or screwdriver bit), then the drill won’t actually accomplish anything. The whole point of these other disciplines is to make up a drill that will work well at accomplishing its task.

Equally important, however, is the recognition that a drill bit by itself is not much good. Could someone conceivably drill a hole in a piece of wood using a drill bit and his own bare hands without the drill? Sure, but it make take several days, weeks, or months, depending on how thick the wood is. The better the drill, the heavier the drill, the more efficient will be its penetration of the wood. Practical theology divorced from the other disciplines is a drill bit that has no bite. This is one reason, incidentally, that I quickly tire of practical theology books that do not do any theology. In my mind, such books are really no better than books of advice. It won’t grab me at all unless the practical theologian proves that his application and practice are, in fact, biblical.

All of the disciplines are equally important, and (even more importantly) mutually dependent. Let no exegete turn up his nose at the fence. Instead, let him know that outside the fence is danger, not freedom. Let the systematician not turn up his nose at exegesis, knowing that it is the lifeblood of his own discipline. Let him not impose non-biblical categories on the text of Scripture. Let neither the exegete nor the systematician forget how the church has wrestled with the text in its history, lest they fall into grievous error that has already been laid to rest. Let none of these forget that all of Scripture is useful to make the man of God complete.

So, what should the pastor do in response to this? Should he become an expert in every one of the disciplines? Yes and no. Seminary training is supposed to be a solid introduction to all the disciplines (and should be done in a very unified way). Pastors do not need to have a Ph.D. to exercise a unified theological encyclopedia in their ministries. What they do need, however, is balance. Most pastors like certain kinds of books in one of the theological fields better than books in the other fields. Or they might like two or three of the fields, but not all of them. Pastors should make a serious effort to direct their reading in a balanced way, especially favoring what I call “summary books.” Any book that helps summarize the state of a particular theological discipline is an extremely helpful book to read. Pastors should read books in all the five major fields of theological studies: exegesis, church history, systematic theology, practical theology, and apologetics. Maybe a rotation is a good idea in this regard.

For people in the pew, take a look to see if your pastor is not very balanced in this regard. Do his sermons seem to have no bite to them, because you can’t see where they arose from the text? Or, are the sermons mere lectures, not having application at all? Or does he try to cram all of Reformed systematic theology into every single sermon? Or, do the sermons stick closely to the text, but never observe wider implications for understanding the Bible as a whole? You can encourage your pastor to broaden his reading, and the sermons will certainly benefit from it.

Similarly, the person in the pew can start reading this way as well. A good introductory book in each discipline is extremely helpful. In this regard, it is also helpful to note that the Puritans and the Reformers did not engage in these disciplines in an atomistic way. They did all of them together whenever they did theology. They practiced a unified encyclopedia quite unconsciously, since the division into separate disciplines only came with the Enlightenment (or, as I prefer, the Endarkenment). So, it is helpful to read pre-modern works as well, since they do not have the error of atomism. If we are not aware of this problem, and take steps to correct it, our churches will suffer greatly because of it. If, however, we look straight at the problem, and take conscious steps to become generalist theologians, the Word will penetrate our hearts more completely and effectively, I believe, and we will know God better. Drill away!

Lane Keister is a minister in the Presbyterian Church in America and is pastor of Lebanon Presbyterian Church in Winnsboro, S.C. This article appeared on his blog and is used with permission.