As churches stray from the biblical teachings, they will generally become more man centered and less God centered. The purity of the church needs to also be examined next to the unity of the church. Unity is God’s will for the church and this is a large way the gospel is displayed to the community. God calls us to seek for unity in both the visible and invisible church. We can do this through being gracious to those in our church in understanding differences, as well as cooperating with likeminded churches to spread the gospel and serve the community.
An important aspect of these two things though is how they relate to one another. Both purity and unity in the church are important, but there are clear situations where the need for purity must be place below a desire for unity (See 1 Cor. 5 and 2 John). There does come a time where doctrinal differences, matters of conscience, and simple practical issues require people to split off from a church or some churches to stop working with other churches. Though Christians should seek to bring change within the church in biblical ways, leaving the church is sometimes the best option. There are many examples of this in Church history. For the first part of the early church, there was unity despite some need for the removal of false teaching. But, the protestant reformation was sparked when Luther raised issues with the Catholic doctrine of his day (as they we taking money from people in exchange for claimed forgiveness from God) and was excommunicated in 1521. Unity apart from the gospel is meaningless. If we set aside the truths of God’s word yet we hold onto unity, this unity will not bring about God’s good will of reaching the nations. Our Goal must be first to proclaim the gospel. When unity and cooperation with other gospel church is possible it should be perused. When unity and cooperation with churches that reject the gospel will hinder that work, unity must be place aside for the salvation of the lost.