Researching pastor, poet and professor, Henry Van Dyke, I found this wonderful hymn he wrote: No Form of Human Framing.
To summarize, he says that we can work like crazy to bring people together, and unite their hearts as one. However, all human efforts are woefully inadequate. In the human realm it CANNOT be done. However, IN CHRIST, we find our unity.
I like the last stanza which says, "Forgive us Lord the folly that quarrels with our friends, and draw us near to thy heart where every discord ends."