*To see the previous post in this ongoing series, click here. Next week I will conclude this series by drawing out certain implications from what has been argued in these posts, and by offering a few practical suggestions for those passionate about pursuing “visible unity” among confessing Christians.
“One is a brother to another only through Jesus Christ. I am a brother to another person through what Jesus Christ did for me and to me; the other person has become a brother to me through what Jesus Christ did for him. This fact that we are brethren only through Jesus Christ is of immeasurable significance…Not what a man is in himself as a Christian, his spirituality and piety, constitutes the basis of our community. What determines our brotherhood is what that man is by reason of Christ. Our community with one another consists solely in what Christ has done to both of us. This is true not merely at the beginning, as though in the course of time something else were to be added to our community; it remains so for all the future and to all eternity. I have community with others and I shall continue to have it only through Jesus Christ. The more genuine and the deeper our community becomes, the more will everything else between us recede, the more clearly and purely will Jesus Christ and his work become the one and only thing that is vital between us. We have one another only through Christ, but through Christ we do have one another, wholly, and for all eternity.” (Dietrich Bonhoeffer, “Life Together”, pp. 25-26)
The Basis of Christian Unity
Unity among believers has its exclusive, ongoing basis both subjectively and objectively in the gospel of Jesus Christ. Subjectively, Christian unity is achieved only derivatively through our own prior reconciliation with God through faith in Jesus Christ. Being reconciled with Him is the indispensable prerequisite for being reconciled to one another (cf. Ephesians 2:1-10 and 2:11-22). As believers seek the Lord individually and corporately in glad response to His mercy, unity will be an inevitable by-product of our single-minded passion for the Lord Jesus, of our sacrificial devotion to the gospel, and of our humble love for God’s redeemed people. A. W. Tozer captured the dynamic of this crucial order cogently:
“Has it ever occurred to you that one hundred pianos all tuned to the same [tuning] fork are automatically tuned to each other? They are of one accord by being tuned, not to each other, but to another standard to which each one must individually bow. So one hundred worshippers met together, each one looking away to Christ, are in heart nearer to each other than they could possibly be were they to become “unity” conscious and turn their eyes away from God to strive for closer fellowship.”
Through Jesus’ death and resurrection, we who are many have become members of one body, stones in one temple, and servants for one kingdom. We must affirm that the only true, legitimate basis of our unity is our Spirit-generated faith in this crucified and risen Jesus who is set forth to us in the Gospel. This statement constitutes a vigorous denial that our unity is founded upon unanimous agreement on secondary theological issues or cherished ministry principles or cultural values that will often diverge between various local churches and ministries. Our unity with one another exists prior to these concerns, and must be staunchly maintained even in the midst of significant diversity of conviction, sense of calling and priorities. Simply because Christ cannot be divided, neither can His people be content with ongoing schisms and divisions among themselves for biblically unacceptable reasons as they engage in their Spirit-driven mission. Indeed, unity is a crucial part of their Spirit-driven mission. This must perpetually be brought to our remembrance.
Objectively, it is of crucial significance that we recognize the basic two-fold ground of unity given to us by the apostolic witness of the New Testament: (1) faithful confession of the gospel in truth, and (2) persevering adherence to a biblical lifestyle marked by repentance and faith, in response to the grace that has been freely lavished upon us in Jesus. Likewise (to state it negatively), the only two legitimate causes of breaking unity are serious deviation from or outright denial of the gospel (Galatians 1:6-9, 4:30, II John 9-11) and flagrant, unrepentant sin in the life of believers (Matthew 18:15-17, I Corinthians 5:1-12, II Thessalonians 3:14-15). I contend that no other secondary issues–period, without exception–ought to be insisted upon as valid conditions for either retaining the bond of unity or for the breaking of fellowship with one another. It is stunningly easy for us to become disproportionately fixated upon our remaining differences—and these are admittedly often substantial and not to be minimized—but we must never allow ourselves to lose sight of the fact that what joins us together in Christ is infinitely more significant than what separates us.
Corresponding to the astounding value the biblical writers place on unity among believers, a number of severe warnings sound forth from their pens against those who would promote or give rise to divisions within the body of Christ (Romans 16:17-18, Titus 3:10-11, Jude 19, Galatians 5:15, 19-21, 26). As Wayne Grudem rightly reminds us, it is “because they are jealous to protect this unity of the church [that] the New Testament writers give strong warnings against those who cause divisions.”
Moreover, the persistent diagnosis of the New Testament concerning the failure to maintain unity is that such a state of affairs is due primarily to misunderstanding the radical nature of the gospel and to God’s pride-destroying grace displayed therein. Unity arises from a correct spiritual apprehension of and response to the gospel in our lives; disunity obtains when the gospel does not root itself deeply enough into our hearts. Just as divisions flow out of boasting in anything characteristic of the “flesh” (leaders, abilities, performance, reputation, theological distinctives, etc.), so unity is the sweet fruit of continually placing our confidence only in the Lord. In this sense, unity among believers always remains a second-order good—it is derivative of our faithful recognition that God’s grace is everything, and that we are nothing and have nothing apart from Him. Our unity is, accordingly, found only in our Lord Jesus, not in anything stemming from or accomplished by us. The basis of Christian unity can be properly summarized with the ancient, poignant dictum of Ignatius: “Where Jesus Christ is, there also is the Catholic Church.”
Finally, I conclude by affirming that my vision and understanding of unity set forth in this series is entirely subject to the Word of God, and thus I am open to being corrected in whatever points I currently fall short of or misconstrue the teaching of Scripture. Above all else, my desire is to see firsthand Jesus’ final prayer increasingly realized among the world-wide community of his followers:
“I do not ask for these only, but also for those who will believe in me through their word, that they may all be one, just as you, Father, are in me, and I in you, that they also may be in us, so that the world may believe that you have sent me. The glory that you have given me I have given to them, that they may be one even as we are one, I in them and you in me, that they may become perfectly one, so that the world may know that you sent me and loved them even as you loved me.” (John 17:20-23).
Soli Deo Gloria
 “The quest for the unity of the Church must in fact be identical with the quest for Jesus Christ as the concrete Head and Lord of the Church. The blessing of unity cannot be separated from Him who blesses, in Him it has its source and reality, through His Word and Spirit it is revealed to us, and only in faith can it become a reality among us.” (Karl Barth, The Church and the Churches, p. 28)
 The Pursuit of God, p. 97
 “In a word, the unity of the apostolic churches was grounded on the only thing they had in common—their common Christianity. Its bond was the common reception of the Holy Spirit, which exhibited itself in one calling, one faith, one baptism.” (B. B. Warfield, “True Church Unity: What It Is,” in Selected Shorter Writings, Vol. 1, p. 302)
 “This unfortunate idea—that the basis of spiritual unity must stand in uniformity of doctrine—has been the poisoned spring of all the dissensions that have torn Christ’s body.” (John Watson, Mind of the Master). This statement, of course, must be seriously qualified to mean “uniformity of doctrine in secondary matters.” Taken as it is, the New Testament writers would often fall under its too-sweeping indictment! Agreement on gospel doctrine is indeed a prerequisite to spiritual unity in the church. Yet given this qualification, I think Watson sounds a necessary note for picky Protestants.
 “Consistent with this New Testament emphasis on the unity of believers is the fact that the direct commands to separate from other people are always commands to separate from unbelievers, not from Christians with whom one disagrees [he cites 2 Cor. 6:14, 17, 2 Tim. 3:5].” (Wayne Grudem, Systematic Theology, p. 877)
 Thus, ongoing dialogue with respect to our differences must assume and flow out of this prior unity that has been given to us in Christ. Visible unity must not be suspended or withheld until all sides see eye to eye on everything—whether that be secondary (albeit often important) theological issues or differences of practical or cultural emphasis: “We should labor to find out what is truth, search for it as silver, and go according to what light we have; but yet so, though we might differ, to ‘keep the unity of the Spirit in the bond of peace,’ and join in all things that we can, and so walk so lovingly that it may appear that, if there are differences, it is merely that which conscience makes.” (Jeremiah Burroughs, Gospel Conversation, p. 150; originally published in 1648)
 For further explanation and defense of this position consult Craig Blomberg, “The New Testament Definition of Heresy (Or When Do Jesus and the Apostles Really Get Mad?),” JETS 45/1 (March 2002): 59-72 (available here)
 “It is important that Christians make sure that divisions and separation are due to genuine convictions and principles, and not to personality conflicts or individual ambition. It is a discredit to the cause of Christ when Christians who hold the same beliefs and goals separate.” (Millard Erickson, Christian Theology, p. 1152)
 “Because we tend to be most aware of the differences and schisms in Christianity, we constantly run the danger of disregarding this—nevertheless truly existing—unity. That which unites all true Christians is always more than that which separates them.” (Herman Bavinck, Reformed Dogmatics: Holy Spirit, Church, and New Creation, Vol. 4, p. 321). Cf. the similar sentiments of C. S. Lewis in his prefatory thoughts in Mere Christianity: “When all is said (and truly said) about the divisions of Christendom, there remains, by God’s mercy, an enormous common ground.”
 “He cannot possess the garment of Christ who rends and divides the church of Christ” (Cyprian, “On the Unity of the Church”). Note also the three reoccurring warnings against “schisms” in 1 Corinthians 1:10, 11:18-22 and 12:25. Many commentators, importantly, see 1:10 as the thesis of the entire letter, with all that follows subordinate to its pastoral function.
 Systematic Theology, p. 876. Compare the emphatically strong warning of the influential early church father Irenaeus: “God shall also judge those who give rise to schisms, who are destitute of the love of God, and who look to their own special advantage rather than to the unity of the Church; and who for trifling reasons, or any kind of reason which occurs to them, cut in pieces and divide the great and glorious body of Christ, and so far as in them lies, [positively] destroy it—men who prate of peace while they give rise to war, and do in truth strain out a gnat, but swallow a camel. For no reformation of such great importance can be effected by them, as will compensate for the mischief arising from their schism.” (Against Heresies, 4.33.7)
 In 1 Corinthians 1-4—an absolutely crucial passage for Christian unity—Paul supports his central admonition in 1:10 by progressively demonstrating that the counter-intuitive nature of God’s grace—as revealed in the gospel (1:18-25), in conversion (1:26-31), in his own gospel proclamation (2:1-5), and in the subordinate, humble role of ministers in the lives of Christians (3:5-4:5)—undercuts every implicit rationale that lay behind the Corinthians’ corrosive divisiveness and fleshly tendency to identify themselves primarily with certain prominent ministers and camps rather than with Christ. The Corinthians fail to maintain their unity in Christ primarily because they have so drastically misconstrued the nature of God’s grace, which ought to lead to boasting in Christ alone (1:29-31) and never in people or camps (1:12-13, 3:1-4, 3:21).
 “Immaturity is one great cause of division. The church at Corinth was divided into warring groups because, says Paul, they were childish. The gospel had not gotten deep enough into their system to make them appreciate what the practice of unity requires.” (J. I. Packer, “Divisions in the Church,” in Shorter Writings of J. I. Packer: Serving the People of God, Vol. 2 p. 30). Frank Thielman concurs with this assessment: “[T]he Corinthians’ discord—because it is based on personal pride—is symptomatic of a profound misunderstanding of the gospel. The essence of the gospel is that God freely chose his people apart from any worthiness of their own and placed them in fellowship with Christ Jesus…the Corinthians have demonstrated a fundamental misunderstanding of who they are in God’s sight and of what God has done for them in Christ Jesus.” (Theology of the New Testament: A Canonical and Synthetic Approach, p. 280)
 To the Smyrnaeans