What Is Systematic Theology?

As Dr. Wayne Grudem explains it, “systematic theology is any study that answers the question, ‘What does the whole Bible teach us today?’ about any given topic.”

This highly organized, topical approach to exploring Scripture is so important that most seminaries require at least one systematic theology course in their degree programs (sometimes called “doctrines” courses). Many of these courses utilize Grudem’s work.

We’ve adapted this post from Dr. Wayne Grudem’s Systematic Theology online course to help answer the question “what is systematic theology, and why should I care?”

Let’s begin by looking at what sets systematic theology apart from other ways to study the Bible and form theological beliefs.

Systematic theology is different from:

Historical theology

Historical theology studies how Christians have understood various theological topics throughout history. This informs us of the insights and mistakes others have made studying Scripture over the centuries. While systematic theology sometimes draws from this historical information, it uses other sources as well.

Philosophical theology

Philosophical theology studies theological topics largely without use of the Bible. It uses the tools and methods of philosophical reasoning, and attempts to discern what can be known about God from observing the universe. This can help us understand right and wrong thought forms in our culture and others. Again, systematic theology sometimes draws from this information, but philosophical theology doesn’t provide a holistic understanding of theological topics.

Apologetics

Apologetics defends the validity of the Christian faith, directly addressing objections to the Bible and Christianity. This helps us connect our topical exploration of Scripture to evangelism, and overcome the specific barriers that an unorganized understanding of Scripture can create.

Ethics

While Systematic theology emphasizes what God wants us to believe and know, Christian ethics emphasizes what God wants us to do—and what attitudes he wants us to have.

Learn more in Wayne Grudem's Systematic Theology online course.

Systematic theology vs. biblical theology

Biblical theology gives special attention to the teachings of individual authors and sections of Scripture, and frames each teaching within the historical development of Scripture. It answers questions like, “How does the teaching about prayer develop over the history of the Old Testament and then the New Testament?” These questions come close to the questions that systematic theology answers, like, “What does the whole Bible teach us today about prayer?”

These disciplines often overlap at the edges, and parts of one study blend into the next. But there’s still an important difference: biblical theology traces the historical development of a doctrine, so your understanding of that particular doctrine changes as the historical setting progresses. Biblical theology also focuses on how the biblical authors and their original audience understood each doctrine.

Systematic theology makes use of biblical theology and often builds on its results. At some points, especially where great detail and care is needed in the development of a doctrine, systematic theology will even use the same methods as biblical theology, analyzing the development of each doctrine through the historical development of Scripture. But the focus of systematic theology remains different: it focuses on the collection and summary of all biblical passages on a subject, and attempts to summarize the teachings of Scripture in brief, understandable, and carefully formulated statements.

Systematic theology is applicable to life today

The term Trinity isn't in the Bible. Neither is incarnation. But both describe concepts based on a combination of biblical teachings. Systematic theology summarizes doctrines about modern-day topics like these.

Nowhere in Scripture do we find doctrine separated from life. Defining systematic theology to include “what the whole Bible teaches us today” implies that application to life is a necessary part of the proper pursuit of systematic theology. Each doctrine connects to the Christian life.

Systematic theology is more organized than regular Bible study

Most Christians practice systematic theology without even realizing it. (Or at least they make systematic-theological statements.) Here are some ways people do this all the time:

• “The Bible says that everyone who believes in Jesus Christ will be saved.”
• “The Bible says that Jesus Christ is the only way to God.”
• “The Bible says that Jesus is coming again.”

Every time a Christian says something about what the whole Bible says, he or she is in a sense doing “systematic theology”—according to our definition—by thinking about various topics and answering the question, “What does the whole Bible teach us today?”

But formal systematic theology has several main differences from the way people usually approach these questions.

1. It treats biblical topics in a carefully organized way. This helps guarantee that all topics receive thorough consideration, and it also provides a check against inaccurate analysis of individual topics. Every doctrine has consistent methodology and doesn’t contradict the others.

2. It treats topics in much more detail. After regularly reading the Bible, a Christian may make a statement like, “The Bible says that everyone who believes in Jesus Christ will be saved.” That’s a perfectly true summary of a major biblical teaching, but in academia, systematic theology may elaborate on what it means to “believe in Jesus Christ,” and what it means to “be saved,” carefully considering the implications of each term.

3. It treats the summaries of biblical teachings more accurately. In formal systematic theology, summaries of biblical teachings must be worded precisely to guard against misunderstandings and exclude false teachings.

4. It treats all relevant Bible passages fairly for each topic. Without formally studying a topic, it’s easy to rely on a few relevant passages without taking the time to find them all.

Systematic theology results in doctrines

A doctrine is what the whole Bible teaches us today about a particular topic. It’s the answer to the questions systematic theology asks. Doctrines can be broad, like “the doctrine of God,” or more focused, like “the doctrine of God’s eternity,” or “the doctrine of the Trinity,” or “the doctrine of God’s justice.”

Learn more in Wayne Grudem's Systematic Theology online course.

Why is systematic theology important?

So why should we bother collecting and summarizing the teachings of individual passages on particular topics? Isn’t it good enough to just read the Bible regularly?

Systematic theology enables us to fulfill the Great Commission

Fulfilling the Great Commission includes teaching—not just evangelism. Jesus commanded his disciples to teach believers to observe all that he commanded:

“Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you; and lo, I am with you always, to the close of the age.” —Matthew 28:19–20

Teaching all that Jesus commanded includes teaching what the whole Bible says to us today. To effectively teach ourselves and others what the whole Bible says, we need to collect and summarize all passages on a particular subject.

If someone asks me, “What does the Bible teach about Christ’s return?” I could say, “Just keep reading your Bible and you’ll find out.” But if they start reading Genesis 1:1, it’ll be a long time before he or she finds the answer to the question. We can teach others most effectively if we can direct them to the most relevant passages and suggest an appropriate summary of the teachings of those passages.

Systematic theology has practical benefits for our lives

1. Studying systematic theology helps us overcome our wrong ideas. We all have areas where our understanding of the Bible’s teaching is lacking. We need to address the total weight of the teaching of Scripture in these areas, so that we can confront our faulty inclinations.

For example, suppose someone doesn’t want to believe Jesus is personally coming back to earth. We could show them a couple verses about Jesus’ return to earth, but they might still find a way to dismiss the force of those verses or read a different meaning into them. But if we show them twenty-five or thirty verses that say that Jesus is coming back, our friend is much more likely to be persuaded by the breadth and diversity of biblical evidence for this doctrine.

2. Studying systematic theology prepares us to answer new questions of doctrine. We can’t know what new doctrinal controversies will arise in the church ten, twenty, or thirty years from now. These new controversies will likely include questions no one has faced very carefully before. People will ask, “What does the whole Bible say about this subject?” Those who have studied systematic theology will be more prepared to answer these new questions.

And this goes beyond formal doctrinal problems of applying Scripture to life. Systematic theology prepares us to answer questions like:

• What does the Bible teach about husband-wife relationships?
• About raising children? About witnessing to a friend at work?
• What principles does Scripture give us for studying psychology, or economics, or the natural sciences?
• How does it guide us in spending money, or in saving, or in tithing?

Theological principles come to bear on every question about applying Scripture to our lives. Those who have learned the theological teachings of the Bible will be more prepared to make decisions that please God.

3. Studying systematic theology helps us grow as Christians. The more we know about God, his Word, and his relationships to the world and mankind, the more we will trust him, praise him, and obey him.

The Bible often connects sound doctrine with mature Christian living:

• Paul speaks of “the teaching which accords with godliness” (1 Timothy 6:3)
• He says that his work as an apostle is “to further the faith of God’s elect and their knowledge of the truth which accords with godliness” (Titus 1:1).
• He also indicates that all kinds of disobedience and immorality are “contrary to sound doctrine” (1 Timothy 1:10).

Trying to understand what the Bible teaches us is like fitting together a jigsaw puzzle. Systematic theology helps us fill in the border and some of the major pieces. But no matter how much we study, we’ll never know everything that the Bible teaches about everything, so our puzzle will have gaps with pieces remaining. The goal of systematic theology is to help Christians put as many pieces into their “theological jigsaw puzzle” as they can, with as much accuracy as possible. The doctrines studied in systematic theology act as guidelines to help us continue filling in other areas and adding new pieces for the rest of our lives.

Criticisms of systematic theology

The conclusions are “too consistent” to be true

Systematic theology draws from every verse in every book that has to do with a given topic, fitting them together with teachings from other books. There are 66 books in the Bible and dozens of different human authors—are we really supposed to believe that their teachings all align on every topic? Some scholars criticize systematic theology for its internal consistency, suggesting that it conforms Scripture to fit our own ideas about the topic.

But if Scripture has been interpreted correctly, “consistency” isn’t an argument against systematic theology. Careful study should always interpret Scripture based on the context of each passage, and systematic theology is no exception. If someone argues that Scripture has been misinterpreted, they should be able to identify specific concerns. Perhaps mistakes have been made, and in that case there should be corrections.

Of course, incompetent scholars in any field of biblical studies can be guilty of bad exegesis. But with those “bad examples,” the scholar is to blame, not the field.

This objection is sometimes made by people who have adopted from our culture the belief that we cannot make universally true conclusions about anything—even about God, from his Word. This skepticism is especially common in universities where, if systematic theology is studied at all, it only utilizes philosophical theology and historical theology. This may include a historical study of the beliefs of early Christians and church history, but not the definitive teachings of the Word of God. In these studies, the Bible is often treated as the work of many human authors who wrote from diverse cultures and experiences over the course of more than a thousand years. This view makes trying to find “what the whole Bible teaches” about any subject as hopeless as trying to find “what all philosophers teach” about it. Evangelicals who see Scripture as the product of human and divine authorship must reject this kind of skepticism.

The starting point determines the conclusions

Some scholars ask, “why are these theological topics treated rather than just the topics emphasized by the biblical authors?” If our traditions and our cultures determine the topics we study and the way we arrange them, will our results be true to Scripture?

Those who make this objection often suggest that the best way to avoid this problem is to limit our topical studies to the field of biblical theology, treating only the topics and themes that the biblical authors emphasize, and following the development of these themes throughout the Bible. But if our goal is to find out what God requires of us in all areas that concern us today, we don’t need to restrict our choice of topics to the main concerns of the biblical authors.

For example, it wasn’t the main concern of any New Testament author to explain “baptism in the Holy Spirit,” or women’s roles in the church, or the doctrine of the Trinity, but these are important areas of concern for us today, and if we’re going to understand and explain “what the whole Bible teaches” about them, we need to look at all the relevant places in Scripture.

We will think something about those subjects. And the alternative is to form our opinions from what we feel to be a “biblical” position on each subject. We may bolster our positions with careful analysis of one or two relevant passages—proof texts—with no guarantee that those passages present “the whole counsel of God” (Acts 20:27). The alternative to systematic theology is too subjective and even more susceptible to cultural pressures, leaving the church theologically immature, like “children, tossed to and fro and carried about with every wind of doctrine” (Ephesians 4:14).

Conclusion

When people ask, “What does the Bible say about ___?” the answer involves looking at more than one verse. And it’s not enough to scour a single epistle, or even the New Testament. If the way we answer these questions doesn’t start with a holistic approach to what the Bible has to say, we’re putting our own words in God’s mouth. Systematic theology gives us an organized, careful way to step back and see what the Bible really has to say, from Genesis to Revelation.

It’s inevitable that someone studying a systematic theology text or taking a course in systematic theology will have many of their personal beliefs challenged, modified, refined or enriched. If you’re beginning such a study, you should firmly resolve to abandon any idea which clearly contradicts by the teaching of Scripture. But you should also resolve not to believe any individual doctrine simply because a course or textbook or teacher says that it’s true. Scripture alone, not “conservative evangelical tradition” or any other human authority, should be the only authority that defines what we believe.

Learn more in Wayne Grudem's Systematic Theology online course.