Every person on the planet is a theologian. That is to say, we all have our own ideas of the various concepts within theology. Let me spend a bit of time demystifying the term.
Theology is simply defined as the study of God. Of course, it has many more branches than theology proper (the theology term for the study of God). Currently, there are two main studies in the area of theology that popular: biblical and systematic. Each of these has their own categories.
Biblical Theology: In Biblical Theology, the point is to study the Bible. That seems rather obvious, and the definition is somewhat crude, so let me refine it a bit. For someone interested in biblical theology, you would search for understanding the Bible in its original intention. Here we have a few different areas in which we do that. There is Old Testament scholarship and New Testament scholarship. The Old Testament scholar would desire to become experts in the Old Testament culture, the Hebrew language, and from there might have some sort of expertise within a specific book of the Old Testament. The New Testament scholar would strive to understand New Testament culture, the Greek language, and might have some sort of expertise within a certain book of the New Testament.
Let me give an example of how this might work. When you read Matthew and Luke, you find many times that they overlap in story. Yet, there are some stories you find in Matthew that are not in Luke, and some that are in Luke that are not in Matthew. The chronology is different. The audience is different. The details are sometimes different. The biblical theologian would ask the question of why they are different. Why does Matthew order the three temptations of Jesus differently than Luke? Why does Matthew focus upon the kingdom of heaven, and the phrase “kingdom of God” is used very seldom, whereas Luke doesn’t use “kingdom of heaven” at all? Why does Matthew record Jesus saying, “If I cast out demons by the Spirit of God, then the kingdom of God has come upon you,” but Luke records, “If I cast out demons by the finger of God, then the kingdom of God has come upon you”?
You can see the focus is not so much upon the definitions of justification, sanctification, salvation, etcetera, but upon understanding the Bible as a whole, and then narrowing down our focus to the minute details of each passage and verse. This is much different than systematic theology.
Systematic Theology: In systematic theology, the focus is upon breaking down the concepts in the Bible into “systems”. What is a system? It is a classification, or a filter, from which we read the Scripture through. We all have these. For example, what is the Church? That basic question is the first step to developing an ecclesiology. Ecclesiology is the study of the Church. That is one of the categories of systematic theology. The way that we come to define our terms and put it all together is based upon gathering all of the verses and passages that say something to each system, and trying to figure out how they work together.
Here is a list of the various systems:
Prolegomena: Discussion before the discussion
Bibliology: Doctrine of the Bible
Theology Proper: Doctrine of God
Christology: Doctrine of Christ
Pneumatology: Doctrine of the Spirit
Anthropology: Doctrine of man
Hamartiology: Doctrine of sin
Soteriology: Doctrine of salvation
Ecclesiology: Doctrine of the Church
Eschatology: Doctrine of last things
The way that you would answer the fundamental questions of each of those topics must harmonize with the way you answer the fundamental questions of all the other topics. For example, if you claim that the Church is the new Israel, you cannot then talk about God’s future plan for Israel. Or, if you were to say that God does not know the future, then you cannot claim that eschatology is the study of what God has decreed for the end times. All systems must harmonize in order to do good systematic theology.
These are the basics of theology. Everyone has at least a basic statement to make in regards to all of this. Even if the basic statement is, “I don’t believe the Bible”, it is a theology. It is our job as faithful Christians to wrestle the Scriptures to come to solid conclusions regarding these subjects.