According to Ephesians 4.3, we have to work hard at preserving the unity of the Spirit in the bond of peace. Contrary to popular belief or cultural hope, we cannot all just get along.
Two things of note about this unity.
First, it's the direct result of Christ's sacrifice on the cross. Not only did the death of Christ reconcile us to God, it also provided the means by which we are reconciled to one another. He broke down the barrier of the dividing wall between Jew and Gentile (2.14-16). We forgive each other as God in Christ forgave us via the cross (4.32). On and on I could go. The hope of the earthly reconciliation of human relationships is the cross. Therefore unity in the church is as important a pursuit as most anything we do.
Second, the unity is fragile but beautiful. It requires pursuit, diligence, every effort. But it's absolutely worth it. One of the main reasons it's so worth it is because unity is its own witness to the Gospel of Jesus (John 17.21). The world doesn't see the kind of unity that should be on display in the church anywhere else, so unity is an apologetic for the Truth of who Jesus is and what He has done. Yes, the Enemy would love to destroy it. He'll use any tool in his arsenal to do so - gossip, self-righteousness, a need for control, and general jealousy to name just a few. And that's precisely why the Holy Spirit commands us to work hard at this unity.
It really is that important for a church to be healthy.
But that's just me thinking thoughts...