The biblical calls to unity are too numerous to list in an article of this size as are the warnings about division and divisiveness. In general, the Bible calls for unity based on the truth of God, and that which causes division is condemned.
Before Jesus’ crucifixion, He prayed that His disciples would be one (John 17:20–23). Some have referred to this as Jesus’ “great unanswered prayer”; however, that is not a proper characterization. All believers are indeed one, united with Christ and with each other. What is often lacking is the practical outworking of that unity.
Divisiveness, the promotion of division, is a serious matter. In Romans 16:17, Paul warns, “I urge you, brothers and sisters, to watch out for those who cause divisions and put obstacles in your way that are contrary to the teaching you have learned. Keep away from them.” In 1 Corinthians 1:10, Paul says, “I urge you, believers, by the name of our Lord Jesus Christ, that all of you be in full agreement in what you say, and that there be no divisions or factions among you, but that you be perfectly united in your way of thinking and in your judgment [about matters of the faith]” (AMP). Division is a result of the flesh, contrary to the fruit of the Spirit.
To see how serious of a matter division is, one need only note the list of sinful tendencies that is included with it: “Now the works of the flesh are evident: sexual immorality, impurity, sensuality, idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, envy, drunkenness, orgies, and things like these. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God” (Galatians 5:19–21, ESV, emphasis added). In the church at Philippi, there were two women whose division was so public and detrimental that Paul calls them out publicly (see Philippians 4:2).
Anyone who causes division in the church should be subject to church discipline: “Warn a divisive person once, and then warn them a second time. After that, have nothing to do with them” (Titus 3:10; cf. Matthew 18:15–17). It is important to note that the unity prescribed in the Bible is not a “unity at all costs.” There can be no unity without truth. In some cases, putting someone out of the church, an action that would seem to be born out of divisiveness, is necessary to preserve unity. Toleration of sin and false teaching does not promote unity, and church discipline up to and including excommunication for sin or false teaching does not promote division.
Sinful division is the result of selfishness, and the only remedy is given in Philippians 2: “So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, complete my joy by being of the same mind, having the same love, being in full accord and of one mind. Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. Let each of you look not only to his own interests, but also to the interests of others” (Philippians 2:1–4, ESV). Paul goes on to present Christ as the ultimate example of the selflessness required to demonstrate unity: “Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant, being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross” (verses 5–8, ESV).
In the words of the proverb, “A perverse person stirs up conflict, and a gossip separates close friends” (Proverbs 16:28). Those who purposefully cause division, incite discord, or provoke rancor are rebelling against God’s design for the church.