Paul tells us to maintain the unity in the body of Christ. We don't create the unity, God does. He makes us one. Jesus prayed that we would be one with Him and with each other just as He is one with the Father. It is His one-ness that we have been given. We preserve, or maintain this unity, this one-ness by loving each other, forgiving each other and caring for each other.
After all, there is "one body and one Spirit...one God and Father of us all." Let's do all we need to do in order to preserve and maintain this unity with God and with each other.