Why does there need to be full Christian unity? What is inherently good about it?
Jesus prayed for unity among believers.
John 17:20-22 New American Standard Bible (NASB)
20 “I do not ask on behalf of these alone, but for those also who believe in Me through their word; 21 that they may all be one; even as You, Father, are in Me and I in You, that they also may be in Us, so that the world may [a]believe that You sent Me.