What verses are commonly cited to support that unity, despite differences, is preferable to dividing the Church?

You have asked a question which is very difficult to answer, even through searching the Bible. Yesterday after reading your question I spent some time researching my study material, and found that as long as we depend on someone’s opinion of what is and is not worthy of disagreement we wind up running around in circles.

So I decided to consult the words of Jesus since he is the ultimate authority, and was surprised at what I found. Before even trying to explain what I found I will give you the Scriptures I used and give you the opportunity to evaluate them yourself, since I too am not qualified to say exactly what Jesus wanted us to learn from his words.

Matthew 16:21 through 23 KJV From that time forth began Jesus to shew unto his disciples, how that he must go unto Jerusalem, and suffer many things of the elders and chief priests and scribes, and be killed, and be raised again the third day. 22 Then Peter took him, and began to rebuke him, saying, Be it far from thee, Lord: this shall not be unto thee. 23 But he turned, and said unto Peter, Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men.

Matthew 6:14 through 16 KJV For if ye forgive men their trespasses, your heavenly Father will also forgive you: 15 But if ye forgive not men their trespasses, neither will your Father forgive your trespasses. 16 Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward.

Mark 14:3 through 7 KJV And being in Bethany in the house of Simon the leper, as he sat at meat, there came a woman having an alabaster box of ointment of spikenard very precious; and she brake the box, and poured it on his head. 4 And there were some that had indignation within themselves, and said, Why was this waste of the ointment made? 5 For it might have been sold for more than three hundred pence, and have been given to the poor. And they murmured against her. 6 And Jesus said, Let her alone; why trouble ye her? she hath wrought a good work on me. 7 For ye have the poor with you always, and whensoever ye will ye may do them good: but me ye have not always.

Mark 9:33 through 37 KJV And he came to Capernaum: and being in the house he asked them, What was it that ye disputed among yourselves by the way? 34 But they held their peace: for by the way they had disputed among themselves, who should be the greatest. 35 And he sat down, and called the twelve, and saith unto them, If any man desire to be first, the same shall be last of all, and servant of all. 36 And he took a child, and set him in the midst of them: and when he had taken him in his arms, he said unto them, 37 Whosoever shall receive one of such children in my name, receiveth me: and whosoever shall receive me, receiveth not me, but him that sent me.

Luke 12:13 through 15 KJV And one of the company said unto him, Master, speak to my brother, that he divide the inheritance with me. 14 And he said unto him, Man, who made me a judge or a divider over you? 15 And he said unto them, Take heed, and beware of covetousness: for a man's life consisteth not in the abundance of the things which he possesseth.

There are many more of Jesus teachings which could be used to show how He apparently wanted Christians to react as far as dissention goes and you might even wish to consider more of them. You can use many of the online and downloadable guides in your study.

For now let me explain what I deduced from these Scriptures:

Matthew 16:21 through 23 Jesus rebuked Peter not because Peter loved him, and was willing to protect him from his enemies. What apparently is not moot about this exchange is that the road to Salvation is not something to be reasoned among men. Referring to Peter as Satan appears to indicate that any vocalizations contrary to the will of God are of the will of Satan. In my world that says the idea that Belief in Jesus as our only propitiation for sin is not debatable, therefore; we should not be diverted by those who say there are other ways to get into Heaven and that is worthy of our defense. That being true it is an argument for unity over dividing the Church since such an attitude if allowed would cause division within the Church.

Mark 14:3 through 7 What seems to jump out in this Scripture is that Jesus does not say that selling the oil and giving the proceeds to the poor is wrong, but instead he is pointing out that The Kingdom of God must take precedence over Earthly cares. We must also consider the fact that an omniscient and omnipotent God could have no poor if that were his will. At this point it is incumbent on us to ask why then does God not do away with poor people. If we take along look at how affluence has affected man’s relationship with God, What we find is that an increase in affluence is inversely proportional to godliness. We need only look at the destruction of 9/11 to understand Earthly possessions fade in comparison to man’s feelings of Eternal security. Not only were Church pews filled to overflowing, but there was a sense of oneness against what threatens us. From this it can be deduced that when it comes to the use of assets the works of God versus the use of assets for earthly purposes is not moot.

Mark 9:33 through 37 What we can extract from this exchange is that Jesus is telling his disciples that there is to be no contention as to who has more authority in the Church. This appears to propose that Unity is paramount and dissention is to be avoided. Each part of the Church has its separate and distinct assignment and no one mission is more important than another. Paul wrote extensively about just that thing.

Luke 12:13 through 15 This is the most telling of the Scriptures being considered. Certainly Jesus has the authority to determine how and by whom his creation is distributed; but instead notice that he said * Man, who made me a judge or a divider over you?* Jesus is in saying this taking this out of the realm of God and putting it in the authority of man. Why would Jesus separate this from the authority of God and leave it to the authority of man?

Although Jesus could have injected Righteous reasoning into the situation He refused to do so, leaving the situation unresolved.

I find no justification for rejection of unity in favor of avoiding division in Jesus teachings, or that the Church should be ruled by common assent as opposed to inviolable precepts. What I do find is Jesus decreed that we should abandon our desires which conflict with good order and discipline in the Church.

Our first decision on where and how to worship God must be predicated on the fact it is God’s Church and we are only a miniscule component of that Church no matter that each of us is the most valuable component in that Church. Christianity was coined as a way to describe the followers of Christ and literally means little Christ. What that means in short that we must emulate Christ and dissention among Christ and his disciples did not exist, and must not exist in the Church today.

All of this is to emphasize that rather than fomenting division within the Church we must acquiesce in favor of unity, and obedience not only to the laws of God, but to the intent of those laws. No Church should deviate from the true worship of God to avoid division within the Church and even though that is the reason we are divided not only into Protestant, Orthodox, Catholic, and many other Denominations; it is not sufficient reason for disregarding the precepts of worship.

I don’t know how you feel, but this would really be a good subject for an open chat room from my point of view. One of the more interesting areas of discussion from where I stand would be in the how does Denominational division effect salvation, since many Denominations have expressed the thought that another Denomination cannot go to Heaven. Within itself that is only a contentious subject, but it would be interesting to know how differing Denominations view this.

To add to the other excellent answers, I have not seen the following verse cited, although it seems to me the most powerful of all:

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 (John 17:20-21, ESV).

Since the O.P. included the Catholic Church as a denomination that stresses unity over doctrine, I will observe that, the Catholic Church takes a more “ontological” view (for lack of a better term) of Christian unity than most other denominations. (The group that most closely shares this view, aside from the Catholic Church, is the Eastern Orthodox Church.)

In the Catholic view, the Church is one, and no action on our part can dismember it. Individuals and groups can, however, be placed at various distances from the one Church to varying degrees, while still participating in some elements of the Church. Vatican II’s Lumen gentium sums this idea up in its famous passage on the unity of the Church:

Church constituted and organized in the world as a society, subsists in the Catholic Church, which is governed by the successor of Peter [i.e., the Roman Pontiff] and by the Bishops in communion with him, although many elements of sanctification and of truth are found outside of its visible structure (No. 8).

An awful lot of ink has been spilled on this passage, but the idea is simple: as a distinct, visible, historical subject, the one Church founded by Jesus Christ subsists (a technical philosophical term that means to exist in the fullest sense) in the Catholic Church. According to this view, only the Catholic Church has the fullness of the means of sanctification and the fullness of truth. The other Christian groups stand in relation to the Catholic Church, in differing degrees of participation.

Hence, the Church does not claim to have the power to expel someone from the Catholic Church. That is why the Church does not “remove” those who obstinately espouse dissident or heretical opinions from its rolls. At most, the Church might excommunicate such persons (keeping in mind that for Catholics, excommunication is not an expulsion, but a censure whose purpose is to bring people to repentance).

This policy is different from, say, that of the Anglican Communion, which has historically “agreed to disagree” on various points of doctrine, some of them very important.

The “ontological” vision of Church unity, in the Catholic Church’s view, is tied to the profound unity of God, as is suggested by the passage from John quoted above. Just as the three Persons of the Trinity are one substance (h*m*ousios), the Church founded by Jesus Christ subsists in a unique historical subject, which (according to Catholics) is the Catholic Church itself.

You've posed a good question.

Many Protestant, evangelical churches, whether independent (non-denominational) or denominational, tend to do two things which, although not necessarily biblical in the strictest sense of the term (i.e., according to the "chapter and verse" method of proof-texting), tend to draw fairly clear doctrinal lines in the sand.

First, they construct a "What We Believe" statement which generally speaking covers the non-negotiables of the faith. Second, they tend to administer discipline on church members and regular attenders (or even on visitors who sow discord among the assembly) who "proselytize" for doctrines which either clearly contradict their churches' "What We Believe" statement or tend to create disunity through needless controversy.

Lines Drawn In the Sand

A typical "What We Believe" statement would say in effect,

If you want to become a member or regular attender of our church [e.g., Main Street Community Church" or "First Presbyterian Church of Anytown"], these are the beliefs which provide and promote unity among us, and we title that list "What We Believe" [or "Doctrinal Statement of Faith," or some such title]

Obviously, each church will likely have a different number of non-negotiables, but I suspect that if you were to compare each and every "What We Believe" statement of all the Protestant, evangelical churches worldwide, you would find remarkable unity in what they consider to be the non-negotiables of the Christian faith.

In part, I suggest, this unity can be traced not only to the clear teaching of the Word (more on that later), but also to the various councils from the distant past which settled such non-negotiables as the deity of Jesus Christ (for example) and are identified by the name of a particular controversy or doctrinal heresy traced to false teachers such as Arius (Arianism), Pelagius (Pelagianism), and Sabellius (Sabellianism), to name but three.

Even though I have not done such a comparative study of the type I've suggested, I suspect the top six would include the following (in no particular order):

• The Deity of Jesus Christ (i.e., Jesus Christ was, is, and ever shall be God in the flesh, his deity confirmed by his having been conceived by the Holy Ghost in the womb of the virgin Mary)

• The Trinity (i.e., God exists in three persons, each of whom is fully divine: God the Father, God the Son, and God the Holy Spirit)

• Salvation (i.e., the vicarious, substitutionary death of Jesus Christ on the cross provides forgiveness of sins and a full and free salvation to all who believe if they simply by faith call upon the name of the Lord. Furthermore, there is salvation in none other besides Christ)

• God's Word (i.e., the 66 books of the Bible comprise God's final, complete, Holy-Spirit inspired and authoritative revelation of all that is needed for Christian faith and practice). [While the definition of inspiration may vary somewhat from denomination to denomination, the unifying factor in most Protestant, evangelical churches is that the Bible is authoritative and, rightly interpreted, is an infallible guide for faith and practice]

• The New Birth (i.e., one's entrance into the kingdom of God is by regeneration only, which the Bible describes as being born again, born from above, or born of the Spirit of God)

• The Return of Jesus Christ (i.e., Jesus Christ will return to earth to do battle with evil and defeat it once and for all, ushering in a new heaven and a new earth, free forever from sin and death and the corrupting effects of the Fall)

These five "articles of faith" comprise at least some of the salient biblical criteria for unity within any given church or denomination within Evangelicalism.

Three Strikes and Yer Out!

Second, most Protestant, evangelical churches administer discipline on an ad hoc basis. That is, they wait for a situation to arise in which the unity of the local assembly is being threatened by either blatant sin and/or false teaching. The Scriptures pertaining to blatant sin are plentiful, and I needn't refer to them. As for false teaching: again, a good "Statement of Faith" aids the church leadership in detecting and dealing with false teaching, which always tends to disrupt the unity of a local assembly, if not an entire denomination!

In the church in which I am currently a member (and have been for about 17 years), a brother was stirring things up by attempting to convince some church members that our church's doctrinal stand regarding Divine election was wrong. Our church, by the way, does not take a stand in its Doctrinal Statement on all five points of Calvinism (viz., Total Depravity, Unconditional Election, Limited Atonement, Irresistible Grace, and Perseverance of the Saints), though it would certainly agree with most--if not all--of them to some degree.

If the gentleman had simply "shared" his point of view with other church members, there would not likely have been an issue. Because he was "proselytizing" for his point of view and insisting that the church leadership was incorrect in their interpretation of Divine election, however, he was brought before the elder board (the "ruling board" of our church, with the Senior Pastor as its titular head), warned, and put under discipline for an unspecified amount of time (meaning: he would continue to be a member in good standing as long as he stopped 1) proselytizing for his point of view, and 2) accusing the church leadership of teaching and preaching false doctrine).

There is not necessarily a single “proof text” which churches use to encourage (and sometimes “enforce”) the unity of the body regarding doctrinal differences; rather, there are many. Safe to say, however, the tenor of the teaching of the New Testament regarding unity within the Body of Christ (both Universal and local) can best be summed up, I suggest, in the following saying:

• In essentials, unity

• In non-essentials, harmony

• In all things, charity

What are the “essentials” of the faith? Again, that depends on a given church’s “Statement of Faith.” I’m assuming, by the way, that most churches do have one. Whatever their statement comprises, however, the clear teaching of the Bible in general, and the New Testament in particular, is that unity in essentials is of primary importance, since as you point out, “a house divided against itself cannot stand.”

What are the non-essentials of the faith? Again, that depends on a given church’s “stand” on the kinds of issues the apostle Paul addressed in Romans 14 and 15, and in I Corinthians 12, for example. Usually these types of issues are culturally derived and change from generation to generation. What was once taboo in most Evangelical churches within certain denominations (and sometimes in different geographical regions within a denomination!) at one time in history may no longer be taboo years later.

What unifies Christians regardless of what they consider taboo is the clear teaching of Scripture that Christians are to “abhor what is evil, and cling to what is good” (even though good and evil may be defined, operationally, in slightly different ways).

Conclusion

In conclusion, rather than list all the Scripture passages I could think of to provide you with biblical bases for defining unity and its opposite, I’ve opted just to outline in perhaps a simplistic way how the tenor of Scripture regarding unity and its opposite is in a sense perhaps more important than a list of specific, chapter-and-verse proof texts.

Perhaps Jesus’ high-priestly prayer in John 17 summarizes uniquely well the kind of unity God expects of His Church, and the primary reason for unity within His Church.

"I do not ask on behalf of these alone, but for those also who believe in Me through their word; that they may all be one; even 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 sent Me (vv.20-23 NASB, my emphasis).

Based on the tenor of Jesus’ teaching in that prayer, the purpose of unity within the Body of Christ is primarily to attract non-believers to His Church, since God proffers his love, grace, and mercy to all people from every people-group (from Gk. ta ethne, the “nations” from Jesus' Great Commission to all believers in Matthew 28:18-20).

Where the world tends to divide people (whether according to color, religion, national origin, sex, socio-economic status, intelligence, culture, language, age, or a host of other criteria or rubrics), the Church of God is to embrace all comers who, regardless of how the world may pigeonhole them, believe in Jesus in accord with the teaching of the apostles (i.e., "through their word,” to which Jesus alluded in his high priestly prayer, above).

Verses regarding unity of doctrine are not as common as the less specific verses regarding unity as a body. Two verses that I have most commonly heard referenced regarding avoiding doctrinal division are:

But avoid foolish controversies, genealogies, dissensions, and quarrels about the law, for they are unprofitable and worthless. - Titus 3:9 ESV

And

Have nothing to do with foolish, ignorant controversies; you know that they breed quarrels. - 2 Timothy 2:23 ESV

But it could be argued that both reference all controversy, and are not limited to church leadership.

One the other hand, Paul addresses this very issue of church doctrinal unity in his first letter to the church in Corinth, and I rarely if ever hear this referenced in that context:

10 I appeal to you, brothers, by the name of our Lord Jesus Christ, that all of you agree, and that there be no divisions among you, but that you be united in the same mind and the same judgment. 11 For it has been reported to me by Chloe's people that there is quarreling among you, my brothers. 12 What I mean is that each one of you says, "I follow Paul," or "I follow Apollos," or "I follow Cephas," or "I follow Christ." 13 Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul? 14 I thank God that I baptized none of you except Crispus and Gaius, 15 so that no one may say that you were baptized in my name. 16 (I did baptize also the household of Stephanas. Beyond that, I do not know whether I baptized anyone else.) 17 For Christ did not send me to baptize but to preach the gospel, and not with words of eloquent wisdom, lest the cross of Christ be emptied of its power. - 1 Corinthians 1:10-17 ESV

A few others that may also be useful in this regard:

17 I appeal to you, brothers, to watch out for those who cause divisions and create obstacles contrary to the doctrine that you have been taught; avoid them. 18 For such persons do not serve our Lord Christ, but their own appetites, and by smooth talk and flattery they deceive the hearts of the naive. - Romans 16:17-18 ESV

And

24 But God has so composed the body, giving greater honor to the part that lacked it, 25 that there may be no division in the body, but that the members may have the same care for one another. 26 If one member suffers, all suffer together; if one member is honored, all rejoice together. - 1 Corinthians 12:24-26 ESV

And

17 But you must remember, beloved, the predictions of the apostles of our Lord Jesus Christ. 18 They said to you, "In the last time there will be scoffers, following their own ungodly passions." 19 It is these who cause divisions, worldly people, devoid of the Spirit. - Jude 1:17-19

I have edited again to include a verse that I almost literally stumbled upon recently (printed on a floor plaque outside a church):

1 So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, 2 complete my joy by being of the same mind, having the same love, being in full accord and of one mind. - Philippians 2:1-2 ESV