Unity among two or more people gets its virtue entirely from something else. Unity itself is neutral until it is given goodness or badness by something else. So if Herod and Pilate are unified by their common scorn for Jesus (Luke 23:12), this is not a good unity. But if Paul and Silas sing together in prison for Christ’s sake (Acts 16:25), this is a good unity.
Therefore, it is never enough to call Christians to have unity. That may be good or bad.
Christian unity in the New Testament gets its goodness from a combination of its source, its views, its affections, and its aims.
Paul tells us to “be eager to maintain the unity of the Spirit in the bond of peace” (Ephesians 4:3). I take that to mean that the Holy Spirit is the great giver of unity. “In one Spirit we were all baptized into one body — Jews or Greeks, slaves or free — and all were made to drink of one Spirit” (1 Corinthians 12:13).
Paul says that pastors and teachers are to equip the saints “until we all attain to the unity of the faith and of the knowledge of the Son of God” (Ephesians 4:13). In other words, the unity we pursue is unity in the truth. Of course, Christian unity is more than shared truth, but not less. Paul piles up the words for common-mindedness in Philippians 2:2, “Complete my joy by being of the same mind, having the same love, being in full accord and of one mind” (see also Philippians 4:2). Everything is to “accord with Christ.” “May God . . . grant you to live in harmony with one another, in accord with Christ Jesus” (Romans 15:5).
To be sure, unifying love in the body of Christ includes a rugged commitment to do good for the family of God whether you feel like it or not (Galatians 6:10). But, as difficult as it is for diverse people, the experience of Christian unity is more than that. It includes affectionate love, not just sacrifice for those you don’t like. It is a feeling of endearment. We are to have affection for those who are our family in Christ. “Love one another with brotherly affection” (Romans 12:10). “Having purified your souls by your obedience to the truth for a sincere brotherly love, love one another earnestly from a pure heart” (1 Peter 1:22). “All of you, have . . . sympathy, brotherly love, a tender heart, and a humble mind” (1 Peter 3:8).
Spirit-rooted, Christ-manifesting, truth-cherishing, humbly-loving unity is designed by God to have at least two aims: a witness to the world, and an acclamation of the glory of God. The apostle John makes the first of these most clear. “A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another. By this all people will know that you are my disciples, if you have love for one another” (John 13:34–35).
“Christian unity includes affectionate love, not just sacrifice for those you don’t like.”
Jesus’s famous statements in John 17 are rooted in the profound spiritual unity between the Father and the Son, and with those whom God has chosen out of the world (John 17:6). “I ask 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 17:21). Note the witness to the world is that the disciples are in the Father and the Son so that the world might believe. This is vastly more — deeply more — than being related through a common organization.
The oneness that shines with self-authenticating glory for the world to see is union with the Father and the Son so that the glory of the Father and the Son is part of our lives. “The glory that you have given me I have given to them, that they may be one even as we are one” (John 17:22). That glory is owing to this: “I in them and you [Father] in me” (John 17:23). From this union with God, and the glory it gives, shines something the world may see, if God gives them eyes to see. God’s aim for this vertically-rooted, horizontal, glory-displaying unity is that he might “gather into one the children of God scattered abroad” (John 11:52).
The ultimate aim of such Christian unity is the glory of God. Hence Paul prays, “May the God of endurance and encouragement grant you to live in such harmony with one another, in accord with Christ Jesus, that together you may with one voice glorify the God and Father of our Lord Jesus Christ. Therefore welcome one another as Christ has welcomed you, for the glory of God” (Romans 15:5–7).
“Do not get drunk with wine, for that is debauchery, but be filled with the Spirit” (Ephesians 5:18). Seek to be led by the Spirit and to bear the fruits of the Spirit (Galatians 5:18, 22–23) for these are the cogs in the wheels of love. If you are a stranger to the Holy Spirit, you will care little for the unity he builds.
Seek to “attain to the unity of the faith and of the knowledge of the Son of God” (Ephesians 4:13). “Grow in the grace and knowledge of our Lord and Savior Jesus Christ” (2 Peter 3:18). Share, by every means you can, what you see of Christ. “Let the word of Christ dwell in you richly, teaching and admonishing one another in all wisdom” (Colossians 3:16).
Cultivate affection across differences for those who are truly your brothers and sisters in Christ. Hate serious blunders, not sincere brothers. Humans have never been good at this. And the philosophical and emotional climate today makes it even harder — since truth claims are only seen as a cloak for power-grabbing. But consider what Spurgeon says and seek to become like him. Notice the intensity of hate and love.
Where the Spirit of God is there must be love, and if I have once known and recognized any man to be my brother in Christ Jesus, the love of Christ constraineth me no more to think of him as a stranger or foreigner, but a fellow citizen with the saints. Now I hate High Churchism as my soul hates Satan; but I love George Herbert, although George Herbert is a desperately High Churchman. I hate his High Churchism, but I love George Herbert from my very soul, and I have a warm corner in my heart for every man who is like him. Let me find a man who loves my Lord Jesus Christ as George Herbert did and I do not ask myself whether I shall love him or not; there is no room for question, for I cannot help myself; unless I can leave off loving Jesus Christ, I cannot cease loving those who love him. (The Metropolitan Tabernacle Pulpit Sermons, vol. XII, 6)
For the sake of a witness to the world, seek out ways to show love for brothers and sisters across boundaries — both the kind of boundaries that should be removed, and the kind of boundaries which commit to the truth (and unity in the truth) forbids you to remove. Do this for the glory of God. Let Francis Schaeffer be your guide.
Spurgeon: “Unless I can leave off loving Jesus Christ, I cannot cease loving those who love him.”
It is in the midst of a difference that we have our golden opportunity. When everything is going well and we are all standing around in a nice little circle, there is not much to be seen by the world. But when we come to the place where there is a real difference, and we exhibit uncompromised principles but at the same time observable love, then there is something that the world can see, something they can use to judge that these really are Christians, and that Jesus has indeed been sent by the Father. (Complete Works, vol. 4, 201, emphasis added)
When all is said and done, ambiguities remain. What kinds of boundaries should define local churches, schools, denominations, conferences, para-church ministries, city-wide prayer gatherings, and evangelistic efforts? Nevertheless, we are not without anchors. We are not without rudder and sails.
We have the stars above and our trusty sextant. In reliance on the word and the Spirit, in humility, we will arrive home — together.
John Piper (@JohnPiper) is the founder and teacher of desiringGod.org and chancellor of Bethlehem College & Seminary. For 33 years, he served as pastor of Bethlehem Baptist Church, Minneapolis, Minnesota. He is the author of more than 50 books, including Desiring God: Meditations of a Christian Hedonist and most recently What Is Saving Faith?