Systematic Theology

by Wayne Grudem

(see note at the bottom of this page for information on how to obtain this book)


What is systematic theology? Why should Christians study it? How should we study it?

Explanation and Scriptural Basis

A. Definition of Systematic Theology

What is systematic theology? Many different definitions have been given, but for the purposes of this book the following definition will be used: Systematic theology is any study that answers the question, “What does the whole Bible teach us today?” about any given topic.

This definition indicates that systematic theology involves collecting and understanding all the relevant passages in the Bible on various topics and then summarizing their teachings clearly so that we know what to believe about each topic.

1. Relationship to Other Disciplines. The emphasis of this book will not therefore be on historical theology (a historical study of how Christians in different periods have understood various theological topics) or philosophical theology (studying theological topics largely without use of the Bible, but using the tools and methods of philosophical reasoning and what can be known about God from observing the universe) or apologetics (providing a defense of the truthfulness of the Christian faith for the purpose of convincing unbelievers). These three subjects, which are worthwhile subjects for Christians to pursue, are sometimes also included in a broader definition of the term systematic theology. In fact, some consideration of historical, philosophical, and apologetic matters will be found at points throughout this book. This is because historical study informs us of the insights gained and the mistakes made by others previously in understanding Scripture; philosophical study helps us understand right and wrong thought forms common in our culture and others; and apologetic study helps us bring the teachings of Scripture to bear on the objections raised by unbelievers. But these areas of study are not the focus of this volume, which rather interacts directly with the biblical text in order to understand what the Bible itself says to us about various theological subjects.

If someone prefers to use the term systematic theology in the broader sense just mentioned instead of the narrow sense which has been defined above, it will not make much difference. Those who use the narrower definition will agree that these other areas of study definitely contribute in a positive way to our understanding of systematic theology, and those who use the broader definition will certainly agree that historical theology, philosophical theology, and apologetics can be distinguished from the process of collecting and synthesizing all the relevant Scripture passages for various topics. Moreover, even though historical and philosophical studies do contribute to our understanding of theological questions, only Scripture has the final authority to define what we are to believe, and it is therefore appropriate to spend some time focusing on the process of analyzing the teaching of Scripture itself.

Systematic theology, as we have defined it, also differs from Old Testament theology, New Testament theology and biblical theology. These three disciplines organize their topics historically and in the order the topics are presented in the Bible. Therefore, in Old Testament theology, one might ask, “What does Deuteronomy teach about prayer?” or “What do the Psalms teach about prayer?” or “What does Isaiah teach about prayer?” or even, “What does the whole Old Testament teach about prayer and how is that teaching developed over the history of the Old Testament?” In New Testament theology one might ask, “What does John’s gospel teach about prayer?” or “What does Paul teach about prayer?” or even “What does the New Testament teach about prayer and what is the historical development of that teaching as it progresses through the New Testament?”

“Biblical theology” has a technical meaning in theological studies. It is the larger category that contains both Old Testament theology and New Testament theology as we have defined them above. Biblical theology gives special attention to the teachings of individual authors and sections of Scripture, and to the place of each teaching in the historical development of Scripture. So one might ask, “What is the historical development of the teaching about prayer as it is seen throughout the history of the Old Testament and then of the New Testament?” Of course, this question comes very close to the question, “What does the whole Bible teach us today about prayer?” (which would be systematic theology by our definition). It then becomes evident that the boundary lines between these various disciplines often overlap at the edges, and parts of one study blend into the next. Yet there is still a difference, for biblical theology traces the historical development of a doctrine and the way in which one’s place at some point in that historical development affects one’s understanding and application of that particular doctrine. Biblical theology also focuses on the understanding of each doctrine that the biblical authors and their original hearers or readers possessed.

Systematic theology, on the other hand, makes use of the material of biblical theology and often builds on the results of biblical theology. At some points, especially where great detail and care is needed in the development of a doctrine, systematic theology will even use a biblical-theological method, analyzing the development of each doctrine through the historical development of Scripture. But the focus of systematic theology remains different: its focus is on the collection and then the summary of the teaching of all the biblical passages on a particular subject. Thus systematic theology asks, for example, “What does the whole Bible teach us today about prayer?” It attempts to summarize the teaching of Scripture in a brief, understandable, and very carefully formulated statement.

2. Application to Life. Furthermore, systematic theology focuses on summarizing each doctrine as it should be understood by present-day Christians. This will sometimes involve the use of terms and even concepts that were not themselves used by any individual biblical author, but that are the proper result of combining the teachings of two or more biblical authors on a particular subject. The terms Trinity, incarnation and deity of Christ for example, are not found in the Bible, but they usefully summarize biblical concepts.

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. Thus a doctrine under consideration is seen in terms of its practical value for living the Christian life. Nowhere in Scripture do we find doctrine studied for its own sake or in isolation from life. The biblical writers consistently apply their teaching to life. Therefore, any Christian reading this book should find his or her Christian life enriched and deepened during this study; indeed, if personal spiritual growth does not occur, then the book has not been written properly by the author or the material has not been rightly studied by the reader.

3. Systematic Theology and Disorganized Theology. If we use this definition of systematic theology, it will be seen that most Christians actually do systematic theology (or at least make systematic-theological statements) many times a week. For example: “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.” These are all summaries of what Scripture says and, as such, they are systematic-theological statements. In fact, 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?”

How then does this book differ from the “systematic theology” that most Christians do? First, it treats biblical topics in a carefully organized way to guarantee that all important topics will receive thorough consideration. This organization also provides one sort of check against inaccurate analysis of individual topics, for it means that all other doctrines that are treated can be compared with each topic for consistency in methodology and absence of contradictions in the relationships between the doctrines. This also helps to ensure balanced consideration of complementary doctrines: Christ’s deity and humanity are studied together, for example, as are God’s sovereignty and man’s responsibility, so that wrong conclusions will not be drawn from an imbalanced emphasis on only one aspect of the full biblical presentation.

In fact, the adjective systematic in systematic theology should be understood to mean something like “carefully organized by topics,” with the understanding that the topics studied will be seen to fit together in a consistent way, and will include all the major doctrinal topics of the Bible. Thus “systematic” should be thought of as the opposite of “randomly arranged” or “disorganized.” In systematic theology topics are treated in an orderly or “systematic” way.

A second difference between this book and the way most Christians do systematic theology is that it treats topics in much more detail than most Christians do. For example, an ordinary Christian as a result of regular reading of the Bible may make the theological statement, “The Bible says that everyone who believes in Jesus Christ will be saved.” That is a perfectly true summary of a major biblical teaching. However, in this book we devote several pages to elaborating more precisely what it means to “believe in Jesus Christ,” and twelve chapters (chapters 32-43) will be devoted to explaining what it means to “be saved” in all of the many implications of that term.

Third, a formal study of systematic theology will make it possible to formulate summaries of biblical teachings with much more accuracy than Christians would normally arrive at without such a study. In systematic theology, summaries of biblical teachings must be worded precisely to guard against misunderstandings and to exclude false teachings.

Fourth, a good theological analysis must find and treat fairly all the relevant Bible passages for each particular topic, not just some or a few of the relevant passages. This often means that it must depend on the results of careful exegesis (or interpretation) of Scripture generally agreed upon by evangelical interpreters or, where there are significant differences of interpretation, systematic theology will include detailed exegesis at certain points.

Because of the large number of topics covered in a study of systematic theology and because of the great detail with which these topics are analyzed, it is inevitable that someone studying a systematic theology text or taking a course in systematic theology for the first time will have many of his or her own personal beliefs challenged or modified, refined or enriched. It is of utmost importance therefore that each person beginning such a course firmly resolve in his or her own mind to abandon as false any idea which is found to be clearly contradicted by the teaching of Scripture. But it is also very important for each person to resolve not to believe any individual doctrine simply because this textbook or some other textbook or teacher says that it is true, unless this book or the instructor in a course can convince the student from the text of Scripture itself. It is Scripture alone, not “conservative evangelical tradition” or any other human authority, that must function as the normative authority for the definition of what we should believe.

4. What Are Doctrines? In this book, the word doctrine will be understood in the following way: A doctrine is what the whole Bible teaches us today about some particular topic. This definition is directly related to our earlier definition of systematic theology, since it shows that a “doctrine” is simply the result of the process of doing systematic theology with regard to one particular topic. Understood in this way, doctrines can be very broad or very narrow. We can speak of “the doctrine of God” as a major doctrinal category, including a summary of all that the Bible teaches us today about God. Such a doctrine would be exceptionally large. On the other hand, we may also speak more narrowly of the doctrine of God’s eternity, or the doctrine of the Trinity, or the doctrine of God’s justice.

The book is divided into seven major sections according to seven major “doctrines” or areas of study:

The Doctrine of the Word of God

The Doctrine of God

The Doctrine of Man

The Doctrines of Christ and the Holy Spirit

The Doctrine of the Application of Redemption

The Doctrine of the Church

The Doctrine of the Future

Within each of these major doctrinal categories many more specific teachings have been selected as appropriate for inclusion. Generally these meet at least one of the following three criteria: (1) they are doctrines that are most emphasized in Scripture; (2) they are doctrines that have been most significant throughout the history of the church and have been important for all Christians at all times; (3) they are doctrines that have become important for Christians in the present situation in the history of the church (even though some of these doctrines may not have been of such great interest earlier in church history). Some examples of doctrines in the third category would be the doctrine of the inerrancy of Scripture, the doctrine of baptism in the Holy Spirit, the doctrine of Satan and demons with particular reference to spiritual warfare, the doctrine of spiritual gifts in the New Testament age, and the doctrine of the creation of man as male and female in relation to the understanding of roles appropriate to men and women today. Because of their relevance to the contemporary situation, doctrines such as these have received more emphasis in the present volume than in most traditional textbooks of systematic theology.

Finally, what is the difference between systematic theology and Christian ethics? Although there is inevitably some overlap between the study of theology and the study of ethics, I have tried to maintain a distinction in emphasis. The emphasis of systematic theology is on what God wants us to believe and to know while the emphasis in Christian ethics is on what God wants us to do and what attitudes he wants us to have. Such a distinction is reflected in the following definition: Christian ethics is any study that answers the question, “What does God require us to do and what attitudes does he require us to have today?” with regard to any given situation. Thus theology focuses on ideas while ethics focuses on situations in life. Theology tells us how we should think while ethics tells us how we should live. A textbook on ethics, for example, would discuss topics such as marriage and divorce, lying and telling the truth, stealing and ownership of property, abortion, birth control, homosexuality, the role of civil government, discipline of children, capital punishment, war, care for the poor, racial discrimination, and so forth. Of course there is some overlap: theology must be applied to life (therefore it is often ethical to some degree). And ethics must be based on proper ideas of God and his world (therefore it is theological to some degree).

This book will emphasize systematic theology, though it will not hesitate to apply theology to life where such application comes readily. Still, for a thorough treatment of Christian ethics, another textbook similar to this in scope would be necessary.

B. Initial Assumptions of This Book

We begin with two assumptions or presuppositions: (1) that the Bible is true and that it is, in fact, our only absolute standard of truth; (2) that the God who is spoken of in the Bible exists, and that he is who the Bible says he is: the Creator of heaven and earth and all things in them. These two presuppositions, of course, are always open to later adjustment or modification or deeper confirmation, but at this point, these two assumptions form the point at which we begin.

C. Why Should Christians Study Theology?

Why should Christians study systematic theology? That is, why should we engage in the process of collecting and summarizing the teachings of many individual Bible passages on particular topics? Why is it not sufficient simply to continue reading the Bible regularly every day of our lives?

1. The Basic Reason. Many answers have been given to this question, but too often they leave the impression that systematic theology somehow can “improve” on the Bible by doing a better job of organizing its teachings or explaining them more clearly than the Bible itself has done. Thus we may begin implicitly to deny the clarity of Scripture (see chapter 6) or the sufficiency of Scripture (see chapter 8).

However, Jesus commanded his disciples and now commands us also 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. (Matt. 28:19-20)

Now to teach all that Jesus commanded, in a narrow sense, is simply to teach the content of the oral teaching of Jesus as it is recorded in the gospel narratives. However, in a broader sense, “all that Jesus commanded” includes the interpretation and application of his life and teachings, because in the book of Acts it is implied that it contains a narrative of what Jesus continued to do and teach through the apostles after his resurrection (note that 1:1 speaks of “all that Jesus began to do and teach”). “All that Jesus commanded” can also include the Epistles, since they were written under the supervision of the Holy Spirit and were also considered to be a “command of the Lord” (1 Cor. 14:37; see also John 14:26; 16:13; 1 Thess. 4:15; 2 Peter 3:2; and Rev. 1:1-3). Thus in a larger sense, “all that Jesus commanded” includes all of the New Testament.

Furthermore, when we consider that the New Testament writings endorse the absolute confidence Jesus had in the authority and reliability of the Old Testament Scriptures as God’s words (see chapter 4), and when we realize that the New Testament epistles also endorse this view of the Old Testament as absolutely authoritative words of God, then it becomes evident that we cannot teach “all that Jesus commanded” without including all of the Old Testament (rightly understood in the various ways in which it applies to the new covenant age in the history of redemption) as well.

The task of fulfilling the Great Commission includes therefore not only evangelism but also teaching. And the task of teaching all that Jesus commanded us is, in a broad sense, the task of teaching what the whole Bible says to us today. To effectively teach ourselves and to teach others what the whole Bible says, it is necessary to collect and summarize all the Scripture passages on a particular subject.

For example, 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 the questioner begins reading at Genesis 1:1 it will be a long time before he or she finds the answer to his question. By that time many other questions will have needed answers, and his list of unanswered questions will begin to grow very long indeed. What does the Bible teach about the work of the Holy Spirit? What does the Bible teach about prayer? What does the Bible teach about sin? There simply is not time in our lifetimes to read through the entire Bible looking for an answer for ourselves every time a doctrinal question arises. Therefore, for us to learn what the Bible says, it is very helpful to have the benefit of the work of others who have searched through Scripture and found answers to these various topics.

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. Then the person who questions us can inspect those passages quickly for himself or herself and learn much more rapidly what the teaching of the Bible is on a particular subject. Thus the necessity of systematic theology for teaching what the Bible says comes about primarily because we are finite in our memory and in the amount of time at our disposal.

The basic reason for studying systematic theology, then, is that it enables us to teach ourselves and others what the whole Bible says, thus fulfilling the second part of the Great Commission.

2. The Benefits to Our Lives. Although the basic reason for studying systematic theology is that it is a means of obedience to our Lord’s command, there are some additional specific benefits that come from such study.

First, studying theology helps us overcome our wrong ideas. If there were no sin in our hearts, we could read the Bible from cover to cover and, although we would not immediately learn everything in the Bible, we would most likely learn only true things about God and his creation. Every time we read it we would learn more true things and we would not rebel or refuse to accept anything we found written there. But with sin in our hearts we retain some rebelliousness against God. At various points there are–for all of us–biblical teachings which for one reason or another we do not want to accept. The study of systematic theology is of help in overcoming those rebellious ideas.

For example, suppose there is someone who does not want to believe that Jesus is personally coming back to earth again. We could show this person one verse or perhaps two that speak of Jesus’ return to earth, but the person might still find a way to evade the force of those verses or read a different meaning into them. But if we collect twenty-five or thirty verses that say that Jesus is coming back to earth personally and write them all out on paper, our friend who hesitated to believe in Christ’s return is much more likely to be persuaded by the breadth and diversity of biblical evidence for this doctrine. Of course, we all have areas like that, areas where our understanding of the Bible’s teaching is inadequate. In these areas, it is helpful for us to be confronted with the total weight of the teaching of Scripture on that subject, so that we will more readily be persuaded even against our initial wrongful inclinations.

Second, studying systematic theology helps us to be able to make better decisions later on new questions of doctrine that may arise. We cannot know what new doctrinal controversies will arise in the churches in which we will live and minister ten, twenty, or thirty years from now, if the Lord does not return before then. These new doctrinal controversies will sometimes include questions that no one has faced very carefully before. Christians will be asking, “What does the whole Bible say about this subject?” (The precise nature of biblical inerrancy and the appropriate understanding of biblical teaching on gifts of the Holy Spirit are two examples of questions that have arisen in our century with much more forcefulness than ever before in the history of the church.)

Whatever the new doctrinal controversies are in future years, those who have learned systematic theology well will be much better able to answer the new questions that arise. The reason for this is that everything that the Bible says is somehow related to everything else the Bible says (for it all fits together in a consistent way, at least within God’s own understanding of reality, and in the nature of God and creation as they really are). Thus the new question will be related to much that has already been learned from Scripture. The more thoroughly that earlier material has been learned, the better able we will be to deal with those new questions.

This benefit extends even more broadly. We face problems of applying Scripture to life in many more contexts than formal doctrinal discussions. 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? In every area of inquiry certain theological principles will come to bear, and those who have learned well the theological teachings of the Bible will be much better able to make decisions that are pleasing to God.

A helpful analogy at this point is that of a jigsaw puzzle. If the puzzle represents “what the whole Bible teaches us today about everything” then a course in systematic theology would be like filling in the border and some of the major items pictured in the puzzle. But we will never know everything that the Bible teaches about everything, so our jigsaw puzzle will have many gaps, many pieces that remain to be put in. Solving a new real-life problem is analogous to filling in another section of the jigsaw puzzle: the more pieces one has in place correctly to begin with, the easier it is to fit new pieces in, and the less apt one is to make mistakes. In this book the goal is to enable Christians to put into their “theological jigsaw puzzle” as many pieces with as much accuracy as possible, and to encourage Christians to go on putting in more and more correct pieces for the rest of their lives. The Christian doctrines studied here will act as guidelines to help in the filling in of all other areas, areas that pertain to all aspects of truth in all aspects of life.

Third, studying systematic theology will help us grow as Christians. The more we know about God, about his Word, about his relationships to the world and mankind, the better we will trust him, the more fully we will praise him, and the more readily we will obey him. Studying systematic theology rightly will make us more mature Christians. If it does not do this, we are not studying it in the way God intends.

In fact, the Bible often connects sound doctrine with maturity in Christian living: Paul speaks of “the teaching which accords with godliness” (1 Tim. 6:3) and 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). By contrast, he indicates that all kinds of disobedience and immorality are “contrary to sound doctrine” (1 Tim. 1:10).

In connection with this idea it is appropriate to ask what the difference is between a “major doctrine” and a “minor doctrine.” Christians often say they want to seek agreement in the church on major doctrines but also to allow for differences on minor doctrines. I have found the following guideline useful:

A major doctrine is one that has a significant impact on our thinking about other doctrines, or that has a significant impact on how we live the Christian life. A minor doctrine is one that has very little impact on how we think about other doctrines, and very little impact on how we live the Christian life.

By this standard doctrines such as the authority of the Bible (chapter 4), the Trinity (chapter 14), the deity of Christ (chapter 26), justification by faith (chapter 36), and many others would rightly be considered major doctrines. People who disagree with the historic evangelical understanding of any of these doctrines will have wide areas of difference with evangelical Christians who affirm these doctrines. By contrast, it seems to me that differences over forms of church government (chapter 47) or some details about the Lord’s Supper (chapter 50) or the timing of the great tribulation (chapter 55) concern minor doctrines. Christians who differ over these things can agree on perhaps every other area of doctrine, can live Christian lives that differ in no important way, and can have genuine fellowship with one another.

Of course, we may find doctrines that fall somewhere between “major” and “minor” according to this standard. For example, Christians may differ over the degree of significance that should attach to the doctrine of baptism (chapter 49) or the millennium (chapter 55) or the extent of the atonement (chapter 27). That is only natural, because many doctrines have some influence on other doctrines or on life, but we may differ over whether we think it to be a “significant” influence. We could even recognize that there will be a range of significance here and just say that the more influence a doctrine has on other doctrines and on life, the more “major” it becomes. This amount of influence may even vary according to the historical circumstances and needs of the church at any given time. In such cases, Christians will need to ask God to give them mature wisdom and sound judgment as they try to determine to what extent a doctrine should be considered “major” in their particular circumstances.

You may want to purchase “Systematic Theology” by Wayne Grudem at your local Christian bookstore. The book is published by Zondervan and is 1290 pages. You may go to or contact Bits & Bytes Computer Resources for the computer-readable form of the book at The cost of the book or CD is under $40.00. We recommend this wonderful book for every Christian library.

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