In addressing the basic question posed by this article, we think it is important to also answer a related question: Should there be  unity not only within each Christian church, but also among the different Christian denominations?

Before we attempt to answer these questions, we want to provide a general definition of the term unity.  According to Webster’s Dictionary, unity is: “the quality of being one in spirit, sentiment, purpose, etc.; harmony.”  This definition seems to focus primarily on similar attitude or objective, and does not seem to necessitate similar belief or doctrine.

But, what does the Bible say about Christian unity?  There are three scriptures on which we will focus.  Several other scriptures mention or allude to the term unity, but they do not address the nature of Christian unity.

[Note:  When we quote Scripture in this article, we use the wording in the New King James Version (NKJV) of the Bible, unless indicated otherwise. When words in a quoted scripture are shown in bold print, the emphasis is our own.]

I. Ephesians 4:1b-3: [W]alk worthy of the calling with which you were called, with all lowliness and gentleness, with longsuffering, bearing with one another in love, endeavoring to keep the unity of the Spirit in the bond of peace.

All of the following Bible commentaries that address this scripture seem to indicate that it  pertains primarily to unity of Christians in terms of spirit, sentiment, and purpose.

Barnes’ Notes on the Whole Bible states with regard to Ephesians 4:1b-3,

The unity of the Spirit – A united spirit, or oneness of spirit. This does not refer to the fact that there is one Holy Spirit; but it refers to unity of affection, of confidence, of love. It means that Christians should be united in temper and affection, and not be split up into factions and parties. . . .  There was occasion among the Ephesians for this exhortation; for they were composed of Jews and Gentiles, and there might be danger of divisions and strifes [sic], as there had been in other churches.

[T]here is always danger of discord where people are brought together in one society. There are so many different tastes and habits; there is such a variety of intellect and feeling; the modes of education have been so various, and the temperament may be so different, that there is constant danger of division.

In the bond of peace – This was to be by the cultivation of that peaceful temper which binds all together. . . . The meaning here is, that they should be bound or united together in the sentiments and affections of peace. It is not mere “external” unity; it is not a mere unity of creed; it is not a mere unity in the forms of public worship; it is such as the Holy Spirit produces in the hearts of Christians, when it fills them all with the same love, and joy, and peace in believing.

In reference to the same scripture, John Calvin’s Commentary on the Bible declares,

Endeavoring to keep the unity of the Spirit. With good reason does he recommend forbearance, as tending to promote the unity of the Spirit. Innumerable offenses arise daily, which might produce quarrels, particularly when we consider the extreme bitterness of man’s natural temper. Some consider the unity of the Spirit to mean that spiritual unity which is produced in us by the Spirit of God. There can be no doubt that He alone makes us “of one accord, of one mind,” (Philippians 2:2,) and thus makes us one; but I think it more natural to understand the words as denoting harmony of views. This unity, he tells us, is maintained by the bond of peace; for disputes frequently give rise to hatred and resentment. We must live at peace, if we would wish that brotherly kindness should be permanent amongst us.

Adam Clarke Commentary provides the following comments about Ephesians 4:1b-3:

Endeavouring to keep the unity of the Spirit in the bond of peace – There can be no doubt that the Church at Ephesus was composed partly of converted Jews, as well as Gentiles. Now, from the different manner in which they had been brought up, there might be frequent causes of altercation. Indeed, the Jews, though converted, might be envious that the Gentiles were admitted to the same glorious privileges with themselves, without being initiated into them by bearing the yoke and burden of the Mosaic law. The apostle guards them against this, and shows them that they should intensely labor . . . to promote and preserve peace and unity. By the unity of the Spirit we are to understand, not only a spiritual unity, but also a unity of sentiments, desires, and affections, such as is worthy of and springs from the Spirit of God. By the bond of peace we are to understand a peace or union, where the interests of all parties are concentrated, cemented, and sealed. . . .

With regard to the same scripture, John Gill’s Exposition on the Whole Bible says,

Endeavouring to keep the unity of the Spirit,…. That is, a spiritual union: there is an union between God and his people, and between Christ and his members, and between saints and saints, and the bond of each union is love; and that it is which knits and cements them together; and it is the last of these which is here intended: the saints are united under one head, and are members of one and the same body, and should be of the same mind and judgment, and of one accord, heart, and affection. . . .

in the bond of peace: by maintaining peace among themselves, and seeking those things which tend to, and make for peace, and spiritual edification; and which is called a bond, in allusion to the Greek word used, which comes from one that signifies to knit, join, and bind together. . . .

Matthew Henry’s Complete Commentary on the Bible states in reference to Ephesians 4:1b-3,

The nature of that unity which the apostle prescribes: it is the unity of the Spirit. . . . The seat of Christian unity is in the heart or spirit: it does not lie in one set of thoughts, nor in one form and mode of worship, but in one heart and one soul. This unity of heart and affection may be said to be of the Spirit of God; it is wrought by him, and is one of the fruits of the Spirit. This we should endeavour to keep. Endeavouring is a gospel word. We must do our utmost. If others will quarrel with us, we must take all possible care not to quarrel with them. If others will despise and hate us, we must not despise and hate them. In the bond of peace. Peace is a bond, as it unites persons, and makes them live friendly one with another. A peaceable disposition and conduct bind Christians together, whereas discord and quarrelling disband and disunite their hearts and affections.

Peter Pett’s Commentary on the Bible makes the following comments on Ephesians 4:1b-3:

‘With all lowliness and meekness, with longsuffering, forbearing one another in love.’ There is to be nothing abrasive about the Christian when dealing with his fellow-Christians. He is to be humble, self-effacing, enduring willingly for Christ’s sake while still firm (but not ungracious) for truth. Each is to be concerned for the other. They are to be concerned for each other’s welfare, for each other’s sensitivities, for each other’s feelings, in the same way that Jesus Himself was while on earth.

‘Giving diligence to maintain the unity of the Spirit in the bond of peace.’ Unity does not just happen, it requires diligence. Like marriage it has to be worked at because we are such awkward creatures. Yet for the Christian there is the great assistance of the Spirit. He is the One Who invokes and seeks to maintain unity. As the One Spirit He combines us as one. And to do so He uses the bond of peace.

‘In the bond of peace.’ The word for ‘bond’ . . . means ‘something that keeps together the whole’. And this bond is to be ‘peace’. Peace with God (Romans 5:1) and peace from God (Romans 1:72 Corinthians 1:2Galatians 1:3), ever linked with His ‘grace’, and above all the peace of God ruling in the heart (Colossians 3:15Philippians 4:7) will be the bond that will enable us to behave rightly towards each other.

And, in regard to the same scripture, The Pulpit Commentaries says,

Striving to keep the unity of the Spirit. [This] is stronger than . . . “endeavoring,” and denotes an object to be carefully and earnestly watched for and promoted. “The unity of the Spirit” is equivalent to the unity of which the Spirit is the Author. In all in whom he works savingly, the Spirit produces a certain oneness in faith, in repentance, in knowledge, in their views of sin, grace, Christ, the world, etc. This oneness exists, and cannot but exist, even when Christians are not careful of it, but the manifestation of it is lost; it seems to the world as if there were no such oneness. It is due to the Spirit, as well as to the interests of the kingdom of God, that the unity of the Spirit be maintained in the bond of peace. [It is] the bond which consists of peace—a peace-loving spirit, a spirit laying more stress on the points in which Christians agree than those in which they differ.

II. Ephesians 4:12-13: [God has given Christians certain spiritual gifts]for the equipping of the saints [Christians] for the work of ministry, for the edifying of the body of Christ,  till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ. . . .

In contrast with the aforementioned Bible commentaries that address Ephesians 4:1b-3, which  evidently pertains primarily to Christian unity in terms of spirit, sentiment, and purpose, apparently all of the following Bible commentaries that address Ephesians 4:12-13 indicate that it pertains primarily to unity of Christians with regard to doctrine.

Barnes declares with reference to this scripture,

Till we all come – Until all Christians arrive at a state of complete unity, and to entire perfection.

In the unity of the faith – The meaning is, until we all hold the same truths, and have the same confidence in the Son of God. . . .

In regard to Ephesians 4:12-13, Gill states,

Till we all come in the unity of the faith,…. These words regard the continuance of the Gospel ministry in the church, until all the elect of God come in: or “to the unity of the faith”; by which is meant, not the union between the saints, the cement of which is love; nor that which is between Christ and his people, of which his love, and not their faith, is the bond; but the same with the “one faith” (Ephesians 4:5) and designs either the doctrine of faith, which is uniform, and all of a piece; and the sense is, that the ministration of the Gospel will continue until the saints entirely unite in their sentiments about it, and both watchmen and churches see eye to eye: or else the grace of faith, which as to its nature, object, author, spring, and cause, is the same. . . .

Pett provides the following perspective on the same scripture:

‘Until we all attain unto the unity of the faith and of the knowledge of the Son of God unto a full grown man, unto the measure of the stature of the fullness of Christ.’

The final aim is that we may attain to that unity to which he has earlier exhorted us (Ephesians 4:3) and to a deeper understanding and knowledge of the Son of God (compare Romans 1:4). . . . The unity of faith is in respect of essential doctrine such as the true divinity of Christ and His work of redemption, not secondary matters.

‘Into a full-grown man.’ Believing Jews and Gentiles form ‘one new man’ (Ephesians 2:15). . . .  This picture is linked with our oneness in Christ in the body. The full-grown man can thus be seen as Christ and His people growing as one into total Christ-likeness and perfect unity. This twofold strand runs through all Paul’s teaching. The one and the many. He stresses both individual responsibility and corporate oneness.

With reference to Ephesians 4:12-13, Matthew Poole’s English Annotations on the Holy Bible declares,

Till we all come, or meet; all we believers, both Jews and Gentiles, (who while in the world not only are dispersed in several places, but have our several degrees of light and knowledge), meet, or come together, in the unity of, &c.

In the unity of the faith; either that perfect unity whereof faith is the bond, or rather that perfect uniformity of faith in which we shall all have the same thoughts and apprehensions of spiritual things. . . .

And of the knowledge of the Son of God; or acknowledgment, i.e. not a bare speculative knowledge, but such as is joined with appropriation and affection.

In regard to the same scripture, The Pulpit Commentaries states ,

To the unity of the faith, and of the knowledge of the Son of God. Both genitives are governed by unity; already there is one faith (Ephesians 4:5), but we all( i.e. all who compose or are yet to compose the body of Christ, the totality of this body) have to be brought to this faith. As in Ephesians 4:5 “faith” is not equivalent to “creed,” or truth believed, but the act of believing. . . .

And, Spurgeon’s Verse Expositions of the Bible says in reference to Ephesians 4:12-13,

[W]hatever spiritual gifts we have, they are not our own to use as we please; they are only entrusted to us that we may employ them to help our fellow-Christians. Beloved brethren and sisters, we are one with Christ, and we are one with each other; and, therefore, we must not look every man upon his own things, but also upon the things of others; and it should be a question of the first importance to every Christian, “How can I best utilize myself for the benefit of the rest of the members of the Church?” Do not ask, “How can I benefit myself?” but let your enquiry be, “How can I be most profitable to my fellow-Christians?”

III. Colossians 3:12-14: Therefore, as the elect of God, holy and beloved, put on tender mercies, kindness, humility, meekness, longsuffering; bearing with one another, and forgiving one another, if anyone has a complaint against another; even as Christ forgave you, so you also must do. But above all these things put on love, which is the bond of perfection. [Note: Although the NKJV translation of this scripture does not mention unity, we have included this scripture because the wording of verse 14 in several other translations  of the Bible mentions unity.  For example, the wording of this verse in the New International Version (NIV) of the Bible says, “And over all these virtues put on love, which binds them all together in perfect unity.”]

Whereas the Bible commentaries that we have cited with regard to both of the other scriptures that we have discussed, the following Bible commentaries indicate that Colossians 3:12-14 stresses the importance of Christians loving God and each other for the purpose of unity or otherwise.

Barnes declares with regard to this scripture,

Put on, therefore, as the elect of God – The fact that you thus belong to one and the same church; that you have been redeemed by the same blood, and chosen by the same grace, and that you are all brethren, should lead you to manifest a spirit of kindness, gentleness, and love.

Which is the bond of perfectness – The idea seems to be that love will bind all the other graces fast together, and render the whole system complete. Without love, though there might be other graces and virtues, there would be a want of harmony and compactness in our Christian graces, and this was necessary to unite and complete the whole. There is great beauty in the expression, and it contains most important truth. If it were possible to conceive that the other graces could exist among a Christian people, yet there would be a sad incompleteness, a painful want of harmony and union, if love were not the reigning principle.

Again, in reference to Colossians 3:12-14, Clarke says,

And above all these things – Upon all, over all; as the outer garment envelopes all the clothing, so let charity or love invest and encompass all the rest. Even bowels of mercy are to be set in motion by love; from love they derive all their feeling, and all their power and promptitude to action. Let this, therefore, be as the upper garment; the surtout that invests the whole man.

Which is the bond of perfectness – Love to God and man is not only to cover all, but also to unite and consolidate the whole. . . . To love God with all the heart, soul, mind, and strength, and one’s neighbor as one’s self, is the perfection which the new covenant requires, and which the grace and Spirit of Christ work in every sincerely obedient, humble believer; and that very love, which is the fulfilling of the law and the perfection itself which the Gospel requires, is also the bond of that perfection. It is by love to God and man that love is to be preserved. Love begets love; and the more a man loves God and his neighbor, the more he is enabled to do so. Love, while properly exercised, is ever increasing and reproducing itself.

Gill states with regard to the same scripture,

put on charity, or brotherly love, for without this all is nothing; they will only be done in show and appearance, in mere guise and hypocrisy, if love is wanting; this actuates and exercises all the rest; it is only from this principle that true sympathy, real kindness, undisguised humility, and meekness, patient longsuffering, and forbearance, and hearty forgiveness proceeds: this is greater, and more excellent, than all the other. . . . [T]his is like a strait and upper garment, keeps close all that is under it, and within it: and it is called

the bond of perfectness; either of the law, and the duties of religion, which it is said to be the fulfilling of . . . the saints, for this is the bond of union between them, which knits and cements them together, so that they are perfectly joined together, and are of one mind and one heart: it is the bond of peace among them, of perfect unity and brotherly love; and a most beautiful and pleasant thing it is for brethren to live and dwell together in unity. . . .

Henry addresses Colossians 3:12-14, as follows:

We are exhorted here to . . . clothe ourselves with love . Above all things put on charity. . . . Let this be the upper garment, the robe, the livery, the mark of our dignity and distinction. . . .  Add to faith virtue, and to brotherly-kindness charity. . . . He lays the foundation in faith, and the top-stone in charity, which is the bond of perfectness, the cement and centre [sic] of all happy society. Christian unity consists of unanimity and mutual love.

In reference to the same scripture, Pett declares,

Having described the old man in terms of his behaviour, he now describes the new man which they are to ‘put on’, in the same terms. ‘Put on’. That is, they must allow the new, spiritual life within them to take over the rule of their lives.

With this encouragement he outlines what kind of people they are to be.  [T]hey are to reveal compassion, kindness, consideration for others, a willingness to humble themselves, a willingness not to fight for their own position and honour, a willingness to bear with the weaknesses of others, a willingness to ‘bear all things, believe all things, hope all things, endure all things’. . ., and a willingness to forgive.

‘Above all these things.’ Love is now declared to be the most important attribute of the Christian, for it sums up in itself all the others, binding them together in a perfect bond. . . .  It is to act towards others ‘as we would that they would act towards us’.

‘The bond of perfectness.’ Either that which perfectly unites together all the other Christian virtues, or as that which perfectly unites together all Christians in true fellowship.

Also, with regard to Colossians 3:12-14, Poole says,

[T]here be particular virtues and graces of the new man they are to put on, or, being new creatures, continually to exercise themselves in.

And above all these things put on charity: [M]utual Christian love or charity is the chiefest [sic] garment the new man can put on. . . .

the bond of perfectness, or . . . the most perfect bond. . . . That perfection of which charity here is said to be the bond, doth most likely respect the integrity and unity of the members of the church. . . .

[T]he Greek word we translate bond here, noting such a collection and colligation of parts whereof a body is composed; and in one Greek copy it is found written, the bond of unity. As a prevailing love to God, and to those who bear his image. . . . [W]hen we entirely love God and his children, we show our love to be the bond of perfectness in returning love to him and his; when by this reciprocal affection both ends of the band of love do meet and are knit together, we become one with God, and in him, through Christ, as one soul amongst ourselves. . . .

Summary and Conclusions

Each of the three scriptures on which we have focused provides a different perspective regarding the nature of Christian unity.  Ephesians 4:1b-3 emphasizes the importance of having the same spirit, sentiment, and purpose.  Ephesians 4:12-13 emphasizes the importance of agreeing on doctrine.  And, Colossians 3:12-14 emphasizes the importance of loving God and each other.

Therefore, we believe it is reasonable to conclude that Christian unity involves all of these characteristics.  Furthermore, it is our belief that it is not absolutely necessary that Christians agree on every doctrine.  Although we believe it is necessary for Christians to agree on fundamental doctrines such as the prerequisite of trusting in Jesus Christ as Savior in order for a person to have assurance of eternal salvation, we do not think it is necessary for Christians to agree on doctrines that are not fundamental, such as the types of roles of women in the church.

The foregoing conclusions suggest that there can be – and should be – a high degree of unity not only among Christians who are members of the same church, but also among Christians who are members of other Christian churches, even if they belong to different denominations, provided that they share the same fundamental doctrines..