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. - Romans 16:17
Causing division is a hurtful thing and never something we should seek to do. Our did say: "Do you think I came to bring peace on earth? No, I tell you, but division" (Luke 12:51). Yet, these words were shared by the very Son of God who came to preach the true way of the kingdom of God. There will be division in the world over his words, those who hate the light will reject his way and words. But in the Church, amongst those who believe in the words of our Lord and are true disciples we should never seek to cause division amongst them. Some people take liberty, even an individual, to speak in a way to promote division and disunity in the Church. They take this liberty from the example of Christ that division will come, but they never consider verses and truths about how the Lord died a martyr death to have a unified people of God. When we cause division amongst that called out people that the Lord bought with His blood we give our Lord a double-smart and injury to his already wounded holy body. Early Church believers were mindful and very protective against causing disunity. False teachers were considered those who promoted such things in the New Testament scriptures.
Paul the Apostle expressed in the verse before the unity that existed in the Church in his day with the statement: "All the churches of Christ send greetings" (Romans 16:16). What a beautiful picture we see that he conveyed greetings from if not "all" but many or "most" of the established assemblies in different cities of the Roman Empire. In our modern day situation we would have to say: "All the churches of Christ send their doctrinal differences and grave concerns for your group." What has probably encouraged more individualistic dividing of the body of Christ is the internet known as the printing press of the 21st century. With a few clicks of a button anyone can post a blog or writing that can be read by thousands with teachings that cause disunity or words that speak against different parts of the body of Christ. Many of these individuals who do this are not part of a larger movement of believers and therefore find it easy to not agree with anyone. Though we can find ourselves not in the place where we are strongly connected with a larger movement of believers this should not be an occasion to cause divisions or hurt. Christianity was never meant to be lived alone but as a community. Though Christianity is divided into larger groups we can seek to be unified with all believers who are disciples and have Jesus Christ in them. It is hurtful to the cause of God in the earth to speak against all organized Christian groups as apostate or non-ideal. Such thinking has never been healthy and rarely promoted the true gathering of God's people as the body of Christ.