Systematic theology is the attempt to put Christian doctrine in a logical order, often starting from one fundamental principle, an approach that goes all the way back to early Christianity.


Systematic theology is the attempt to organize all Christian doctrines in a logical order. The Christian church has been practicing this type of theology since the very early stages of the Church, although the form in which we see it today developed in the middle ages. Major works of systematic theology were also produced throughout the Reformation, with the Institutes of the Christian Religion (John Calvin) and the Westminster Confession of Faith being two well-known examples. Systematic theology often starts with the doctrine of God or the doctrine of Scripture, with the latter being more common in modern works. These sections are then followed by sections on the work of God in creation and providence, on the Fall and the nature of sin, on the work of God in redemption, and finally on the nature of the church and the end of history. Within Evangelical circles, this last section is currently the most debated, as it touches on the gifts of the Spirit and the second coming of Christ.


Systematic theology is an attempt to put Christian doctrines in a logical order. As we know it today, it originated in the middle ages, but it has antecedents that go back almost to New Testament times. A systematic approach to Christian doctrine first appears in the second-century baptismal confessions that later formed the basis for the Apostles’ and Nicene Creeds. In these statements of faith, we find a Trinitarian pattern—God the Father is put first, followed by God the Son, and finally by God the Holy Spirit. At times, there is also an appendix of miscellaneous items, like belief in the communion of saints or in eternal life, which do not fit readily into a scheme based on the Persons of the Godhead.

The first person to go beyond this to compose a systematic treatise of Christian doctrine was John of Damascus (675–749?). John was a Greek Orthodox theologian who wanted to expound the teaching of the Church, and he did this by arranging his subject in four books with a total of 100 chapters. In Book One (14 chapters), he dealt with the unity of God, the Trinity, and the divine nature. In Book Two (30 chapters), he gave an outline of creation – spiritual (angels and demons), material, and mixed (the human race). Book Three (29 chapters) discourses at length on Christology, and Book Four (27 chapters) includes a number of miscellaneous items, ranging from the resurrection life to the Lord’s Supper, the status of Mary and the canon of Holy Scripture. John was so successful that his work became and remains the classical expression of Eastern Orthodox theology. Even today it is often cited as authoritative, although it was never formally approved by any Church council.

John’s work was eventually translated into Latin and made available to Western Europeans, but it was many centuries before anyone tried to imitate him. The first person to do so successfully was Peter Lombard (1090–1160), whose four books of Sentences became the standard work of Western theology until the Protestant Reformation. Like John of Damascus, Peter Lombard divided his subject into four parts, beginning with the doctrine of God the Trinity. From there he dealt with creation, then with the incarnation of Christ (salvation) and finally with the signs, or sacraments of the gospel. His technique was to extract evidence for these things from the writings of the Church Fathers (mainly Augustine, Jerome, Hilary of Poitiers and Gregory the Great) which he then arranged in a systematic order and commented on.

Peter’s original work was edited and further systematized by his younger contemporary Alexander of Hales, and it soon became the standard source for the teaching of Christian doctrine in the schools of theology that were then appearing. Students were expected to compose dissertations on some part of the Sentences and defend them in the presence of their professors, who would then decide whether or not to grant them a university degree. Hundreds of these dissertations still survive, including one by Martin Luther, who began his teaching career by commenting on Peter Lombard.

Peter’s method was systematic but not comprehensive, which left scope for his successors to fill in gaps and improve on what he had achieved. Scholastic theology, as this method is known, quickly developed into a science of its own. Its most famous exponent was Thomas Aquinas (1226–1274), whose Summa contra Gentiles (Summary against the Gentiles) and later his massive Summa Theologiae (Summary of Theology) are its greatest monuments. The Summa Theologiae was never finished, but it represents a considerable advance on Lombard’s Sentences. It relies less on quotations from the Church Fathers and develops its themes with more detailed arguments drawn from a mixture of Scripture, the Fathers, and philosophical arguments. Thomas was less widely read in his own time than he was to become later on, partly because of the massive bulk of his writings and partly because, like everyone else in those days, he saw his work as a commentary on the Sentences, which remained the chief authority for doctrine.

The dominance of Scholastic theology, and in particular of Lombard’s Sentences, was successfully challenged at the time of the Reformation. The rediscovery of many ancient sources, especially from the Greek-speaking East, and a renewed emphasis on Scripture as the only legitimate basis for Christian theology, made it necessary to produce a new textbook of the subject, which John Calvin (1509–1564) managed to do in his Institutes of the Christian Religion. The Institutes went through five editions in Latin and French, expanding their treatment as they went. Today, the 1559 version is regarded as definitive and it is still widely studied by Protestants, many of whom regard it as the finest expression of Reformed theology. Like Peter Lombard, Calvin divided his work into four books. The first one deals with God as Creator (basically the Father and the Trinity), the second with God the Redeemer (basically Christology), the third with the dispensation of grace (largely devoted to the work of the Holy Spirit), and the last to external manifestations of this—the church, the ministry, the sacraments, and the role of civil government.

The Reformation era saw a new lease of life for systematic theology, as can be seen in the numerous confessions of faith that different groups of Protestants produced. The earliest ones were only systematic in a very loose sense, but as time went on, they became more sophisticated. By common consent, the Westminster Confession of Faith (1646) was the most highly developed of them all. Intended to be common to England, Scotland, and Ireland, it fell victim to the civil wars in the British Isles, though it was reinstated in Scotland in 1690 and remains one of the defining standards of Presbyterian churches around the world. A slightly revised form of it was adopted by the English Baptists as the Second London Confession (1689), though it is less widely known today.

An important aspect of these confessions changed in approach from the appearance of the Second Helvetic Confession (1566). Before that time, systematic theology had always started with the doctrine of God, but that now gave way to the priority of Scripture, as the source of Christian teaching and the doctrine of God was put in the second chapter, a pattern that is still dominant today.

Systematic theologies became less popular in the eighteenth century, as confessionalism declined and Enlightenment skepticism made headway, but there was a certain revival after 1800. The most famous and long-lasting systematic theology of the nineteenth century is Charles Hodge’s Systematic Theology, first published in 1872–1873 and still frequently reprinted. Next to Calvin’s Institutes, it has been the most widely used systematic theology textbook in the Reformed tradition, where it has attained a certain iconic status.

In the past generation, systematic theology has undergone a revival, especially among Evangelicals. Major works by Wayne Grudem, Robert Reymond, Millard Erickson, Michael Horton, and Gerald Bray have sold well, but it is still too early to say whether this trend will last. What does seem clear is that it is mostly an attempt to encourage Evangelicals to think systematically about their faith. None of these theologies are particularly original in content or presentation, but as the target audience is unused to the genre, this probably matters little. Other branches of the Church have remained largely untouched by this phenomenon, and it may be that Evangelicals will come to be regarded as the most intellectual Christians because of their apparent interest in the subject.


All systematic theology starts from a fundamental principle, which is then expanded and developed to embrace the entire range of Christian teaching. Usually this principle is either the doctrine of God or the doctrine of Holy Scripture, with the latter being more common in modern times. The reason for this is that the Bible is the basis of academic theology, and among Protestants it is recognized as the only permissible source for Christian doctrine. In practice, this means that the nature and extent of Scripture must be examined before its contents can be applied to Christian teaching, and so questions relating to its infallibility or the extent of the canon tend to be emphasized more than they were in earlier times.

The doctrine of God, which now usually comes immediately after Holy Scripture, is almost always subdivided into the oneness of the divine being and the threeness of his Persons. It is the tradition of Western theology to begin with the one and move on to the three, a method that can be justified from the Bible, which reveals the oneness of God in the Old Testament and the Persons of the Trinity in the New. Proponents of this approach may choose a theme like love (Augustine) or revelation (Karl Barth) and then look at the Trinity as a pattern revolving around this principle. God may then be seen as the Lover (Father), the Beloved (Son) and the Love that flows between them (Holy Spirit), or correspondingly, as the Revealer, the Revealed and the Revelation. Recently, Gerald Bray has attempted to take the principle of divine love and apply it across the board, combining the inner nature of the divine being with its outward expression in the Bible. He continues to put the doctrine of Scripture ahead of the doctrine of God but does so in a way that combines them by making the former an expression of the latter.

Next in the pattern of systematic theology comes the work of the Persons of the Godhead. This usually begins with the doctrines of creation and providence, in which the Father plays a leading (though not exclusive) role. This may be subdivided into different types of creation, including the purely spiritual (angels), the purely material (animals, plants and inert objects), and the human race, which is both spiritual and material.

After that come the doctrines of sin and the fall, which form the necessary link between creation and redemption. Had the creation not fallen, redemption would not have been necessary, or would have taken a very different form. Again, there may be a subdivision into the fall of spiritual creatures (demons) and the fall of mankind, with its effects on the rest of the created order. It may also extend to coverage of other religions, which Christians see as attempts by human beings to find the answer to the human plight, but which partake of the nature of sin because they are unenlightened by divine grace. It may also be here that the systematic theologian will deal with heretical deviations from Christianity and with atheism, which in Christian eyes is the result of rebellion against God.

The next section of Christian theology, and the one that is often given greatest prominence, especially in Protestant circles, is what is sometimes called the ordo salutis (“order of salvation”). The order of salvation starts with the covenant(s) that God has made with his human creatures. Theologians differ as to whether God made a covenant with Adam, but he certainly did with Noah after he destroyed the world in the flood. This was a covenant of preservation, a promise from God that he would not destroy the world because of human sin. The next stage was the granting of a special covenant, sometimes misleadingly known as the covenant of “grace” to Abraham. This covenant promised salvation to God’s chosen people, who were Abraham’s descendants. There is a dispute between Jews and Christians about who these descendants are. Jews restrict it to the physical offspring of Isaac, the child of promise given to Abraham in his old age. Christians, on the other hand, apply it to all who share the faith of Abraham, regarding “descent” as more spiritual than physical.

The Abrahamic covenant was later renewed with Moses and David. It came to be manifested in three so-called covenant “offices”—prophet, priest and king. In ancient Israel no one person could occupy all three of these offices, but they were combined and fulfilled in Christ. Not only was he prophet, priest, and king, but he was also the prophetic word, the priestly sacrifice, and the kingly authority. Christians believe that the coming of Christ, the Messiah promised to the Jews, made the Jewish form (dispensation) of the covenant redundant. This was a blessing because the old dispensation was one of law, which could point out the nature of sin but could do nothing to remove it. The new dispensation, in contrast, was one of freedom from the curse of the law. Some theologians argue that the law was abolished, but most agree that it was fulfilled in Christ so that it could be internalized in the life of the Christian and made no longer necessary in its original form.

Christ fulfilled the covenant by his life, death, and resurrection, a pattern that is recounted in the ancient Creeds and repeated in modern systematic theologies. By his life, he fulfilled the demands of the Father for obedience to his word. By his death, he paid the price for human sinfulness and made it possible for the Father to forgive those who had rebelled against him. By his resurrection, he gave his followers a new and eternal life that is still being worked out in believers on earth but is fulfilled in and by those who have gone to heaven.

Finally, systematic theology concludes with a description of the Christian life that begins with the sending of the Holy Spirit on the day of Pentecost, embraces the foundation and ongoing life of the Church, and ends with the eschatological return of Christ and the last judgment. It is here that the greatest controversies are found at the present time. Some believe that the reign of the Holy Spirit normally includes the grant and practice of extraordinary spiritual gifts like speaking in tongues, while others deny this and even claim that the giving of such gifts has now ceased. The details of Christ’s return are frequently debated because nobody knows for sure when or how it will occur. Finally, there is disagreement about what will happen to those who are not chosen for salvation. Will they suffer eternal punishment, will they be redeemed by some hitherto unrevealed act of God’s grace, or will they simply be annihilated? The first of these options is the standard and traditional one.

Different theologians will advocate their own interpretations of these doctrines but the overall presentation of them remains essentially the same. In the final analysis, all theology is systematic because there is only one God and his mind is a coherent whole. Even if it is not fully revealed to us, his plan must make sense and be “systematic” in some way, though there may be gaps in our understanding that will not be filled until the end of time when all things will be revealed.

Further Reading

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