In the nineteenth century, leading Southern Baptist theologian J. L. Dagg wrote this with regard to the relationship of ecclesiology to other doctrines:
Church order and the ceremonials of religion, are less important than a new heart; and in the view of some, any laborious investigation of questions respecting them may appear to be needless and unprofitable. But we know, from the Holy Scriptures, that Christ gave commands on these subjects, and we cannot refuse to obey. Love prompts our obedience; and love prompts also the search which may be necessary to ascertain his will. Let us, therefore, prosecute the investigation which are before us, with a fervent prayer, that the Holy Spirit, who guides into all truth, may assist us to learn the will of him whom we supremely love and adore.
As evangelical Protestants, we are rightly often first in line to affirm that the doctrine of the church is less important than a heart twice-born. Our Reformation heritage hands us five solas and to think of an additional sola ecclesia is like adding a sixth Istar to the Third Age of Middle Earth, i.e. unthinkable. As such, evangelicals are not as often quick to affirm that wrestling with and arriving at sure ecclesiological convictions, as Dagg suggests, is a worthwhile exercise.
Why should we, then, study the doctrine of the church? To answer that, we need to clarify ecclesiology’s rightful place among and functional posture toward other doctrines.
ECCLESIOLOGY’S RIGHTFUL PLACE
As one reads and studies the Bible, there is a growing realization that some doctrines are more significant than others—not in terms of truthfulness or ultimate value but in terms of priority. In 2005, R. Albert Mohler Jr. provided a word of great clarity to his reading audience with his article, “A Call for Theological Triage and Christian Maturity.” In this article, he explains,
A trip to the local hospital Emergency Room some years ago alerted me to an intellectual tool that is most helpful in fulfilling our theological responsibility. In recent years, emergency medical personnel have practiced a discipline known as triage–a process that allows trained personnel to make a quick evaluation of relative medical urgency. Given the chaos of an Emergency Room reception area, someone must be armed with the medical expertise to make an immediate determination of medical priority. Which patients should be rushed into surgery? Which patients can wait for a less urgent examination? Medical personnel cannot flinch from asking these questions, and from taking responsibility to give the patients with the most critical needs top priority in terms of treatment. …
A discipline of theological triage would require Christians to determine a scale of theological urgency that would correspond to the medical world’s framework for medical priority. With this in mind, I would suggest three different levels of theological urgency, each corresponding to a set of issues and theological priorities found in current doctrinal debates.
Mohler then unveils a method for organizing doctrines in three levels: first-order (fundamental truths of the Christian faith), second-order (areas where believing Christians may disagree, but with division, i.e. ecclesiology), and third-order doctrines (areas where believing Christians may disagree yet remain in fellowship, i.e. eschatology). This idea of theological triage has proven helpful for navigating seasons of theological foment and fellowship.
To consider this further as it relates to ecclesiology, I find it helpful to look to another earlier president of Southern Seminary. John Broadus, in the late nineteenth century, focused on the Great Commission (Mt 28:16-20) in his sermon, entitled “The Duty of Baptists to Teach their Distinctive Views,” to explain that the commands of Christ given to the disciples consisted of what he termed both “the internal and the external elements of Christian piety.”
The internal elements, Broadus explains, are more crucial to the Christian faith as they relate to individuals and their relationship to their Creator. However, Broadus clarifies that any primacy given to the internal elements does not mean that the external elements have little value or lack importance. Broadus reasons that if Christ and his apostles gave commands relating to external elements such as the “constitution and government” of churches, then it “cannot be healthy if they are disregarded.”
ECCLESIOLOGY’S FUNCTIONAL POSTURE
Therefore, as one reads and studies the Bible, there is also the growing realization that the local church functions as a repository not only to receive and transmit the internal or first-order message of the gospel to the current generation, but also to preserve that message for future generations. The external or second-order commands given for the purposes of ordering and governing the church are essential for this task, even though they are not as important as the internal or first-order message.
When Paul writes to Timothy to instruct him in “how one ought to behave in the household of God,” Paul describes the local church as the “pillar and buttress of truth” (1 Tim 3:15). The idea of the local church functioning as a pillar (Gk. stulos) and a buttress (Gk. hedraiōma) creates a picture of an intentionally designed (i.e. ordered) structure that, through its strength, has been prepared both to uphold (i.e. present or proclaim) an object as well as protect (i.e. preserve) an object. Jesus’ promise in Matthew 16:18 that “the gates of hell will not prevail against” the church, reinforces the idea that the local church has been given as an indestructible fortress of strength held together by Jesus Christ himself (Col.1:17).
As a result, Jesus and his apostles have given commands of an external or second-order nature that must be taught and implemented. But for what purpose?
The object given to the local church to uphold and protect is the “truth.” The “truth” is the message of eternal life – the substance of the internal or first-order commands of Christ (1 Tim 2:4; 2 Tim 2:25). The New Testament teaches that this “truth” was, and is, to be handed over or delivered from one generation to the next through the local church:
Luke speaks of this at the beginning of his Gospel when writing to assure Theophilus of the certainty of the things he had been taught. Luke states that he has written an “orderly account” of the things that “those who from the beginning were eyewitnesses and ministers of the word” had “delivered” (Gk. paredosan) to Luke and the other apostles (Lk. 1:1-4).
Likewise, Paul instructs Timothy and the Ephesian Church to “guard the good deposit” (Gk. parathēkēn), a reference to the entire message of the gospel he had taught and given to them. In a broad sense, the purpose of all of Paul’s letters is to deliver the “truth” not only to his immediate recipients, but also to all who will read his letters and implement the commands in local churches (Col. 4:16).
Jude reinforces the notion that the “truth” is the object the local church exists to proclaim and protect. In Jude 3, he explains that “the faith,” or the gospel message of eternal life, has been delivered (Gk. paradotheisē) to the saints. That is to say, the internal or first-order command of salvation through Jesus Christ has been handed down to Christians who live out the Christian life in local churches. Jude states that this delivering was done “once for all” (Gk. hapax), referencing the complete and final nature of the message rather than communicating that the message had no further need of transmission.
In sum, these New Testament commands that speak of the “truth” are primary or, in Mohler’s triage analogy, are first-order and essential. However, the external commands that speak clearly to the order, practice, and health of the local church, while secondary, should not receive treatment as unessential.
As Dagg said, they are “less important than a new heart,” yet, the local church also has a duty to carry forth and teach disciples to observe these second-order commands in obedience to Matthew 28:20. For, though second-order, they are nonetheless given by the Lord Jesus and, as Dagg reminds, our love for Christ and for his disciples, present and future, prompts our joyful obedience.
WHY STUDY ECCLESIOLOGY?
How does ecclesiology relate to other doctrines? The answer is found in the heart and practice of the mission of the local church herself. In a sentence, the local church, the “pillar and buttress of truth,” exists to “guard the good deposit” and “deliver” it to future generations.
Understanding ecclesiology’s rightful place among other doctrines and then grasping how the Gospel-centered nature of the church positions that doctrine in service of the Great Commission is just the grand beginning of the treasures to be found in the worthwhile pursuit of the study of the doctrine of the church.
This essay was shaped by a chapter I recently published in Jason K. Allen, ed. The SBC and the 21st Century (B&H Academic, 2016).
 J. L. Dagg, Manual of Church Order (Charleston, SC: Southern Baptist Publication Society, 1858), 12.
 For a similar discussion of “Major” and “Minor” doctrines, see Wayne Grudem, Systematic Theology: An Introduction to Bible Doctrine (Zondervan, 1994), 29-30.