Many preachers will not admit that they have a “system of theology.” They like to think that they believe the Bible and only the Bible. The fact is, however, that everyone has a system of theology whether they admit it or even realize it. There is nothing wrong with having a system. In fact, acknowledgment of a system demonstrates that one has a comprehensive grasp of Bible knowledge and Scriptural truth that provides a framework within which one interprets life.
More importantly, the theological system provides the framework within which each portion of Scripture is to be interpreted and thus preached. When one preaches on Acts 16:31, for example, the preacher may draw on the entire doctrine of faith to help elucidate this text. When preaching on John 3:3 he may draw on the entire body of teaching regarding regeneration. When preaching on 1 Thessalonians 4:16-17, a verse often used to “prove” many things that it does not really say, the preacher will draw on the entire teaching regarding the second coming to ensure proper interpretation and application of this text.
This last example leads us to another important function systematic theology: the system of theology provides a control over the interpretation of the text. That is, systematic theology establishes boundaries that the preacher must stay within in order to do justice to the whole of Scripture. This is a most crucial function. An obvious example is James 2:17. When preaching this text, the preacher must be diligent to draw from the entire systematic teaching regarding justification to ensure that justification by faith alone is taught.
These functions are most evident with regard to Christological texts. The historic teaching of the church regarding the deity of Christ and the truth of the Trinity had as its purpose to refine and further explain the Scriptural teaching with respect to the person of Christ. Since the teaching about the work of Christ stands or falls in relation to the person of Christ, this doctrine cannot be underestimated. However, many preachers fail to do justice to the Scriptures relating to the person of Christ, often because they themselves have a diminished understanding of Christology. Others fail in this respect because they fail to see the importance of this doctrine beyond its usefulness in evangelistic preaching.
The fact is, however, that the usefulness or practicality of a doctrine does not determine how often it should be preached, if ever. Instead, the clear teaching of Scripture and the prominence afforded to a doctrine by Scripture determines its necessity. Sadly, though, many preachers and teachers of the Bible fail to see the importance of a precise statement of the Trinity and the deity of Christ when preaching redemption. They stumble over the correct definitions and do an injustice to the Savior by either erring too far on one side or the other. If one does not understand who Christ is and what He did, then he cannot preach the truth about Him unless it happens by accident. If the preacher doesn’t preach the truth about Christ, then those he leads in worship cannot worship Him in truth because they do not know the truth about Him.
In light of the great help that one’s theological system may provide in the pulpit, one must be careful, however, not to let the theology overtake the text. If one is preaching from Philippians 2:5-10 about the humiliation of Christ by his taking on humanity, it is wrong to use systematic theology to minimize the humanity of Christ in order to emphasize his deity. That not only does an injustice to the text, it does an injustice to the body of Christ by giving them a skewed picture of the person of Christ.
The same may be true of many doctrines. For example, many who preach in Calvinistic churches, such as this author does, may fear calling for a decision since such a method has been abused by many who do not share our theology. But the fact is, Paul called for his listeners to choose Christ by repenting and believing and yet his teaching on election and predestination is very clear. If preaching a text such as 2 Thessalonians 1:9-10, where Paul uses an aorist participle to draw attention to a believer’s past act of faith at conversion, it is wrong for the preacher to focus on the believer’s life as a continuing act of faith. It is true that the believer’s life is a continuing act of faith and the preacher may choose to demonstrate the contrast, but the text emphasizes the active decision of one who comes to Christ and that is where the focus of the sermon should lie. The text must speak its own truth, not the truth the preacher thinks it should speak, even when the preacher has the most noble of intentions for doing so.
Likewise, the preacher should allow the text to choose his theology rather than his theology, his text. It is the Scriptures that give life and in order for them to do so they must be proclaimed faithfully. In selecting which books or passages to preach through, the preacher may select portions of Scripture that allow him a well-rounded cycle of theological preaching. If one is following a pattern of preaching through Bible books, as the true expository preacher will do, he must be careful not to select books that cater to his theological whims, but must prayerfully seek the guidance of the Spirit to ensure that the “whole counsel of God” is proclaimed.