In Francis Schaeffer's The Mark of A Christian we read this amazing story that happened among the Brethren groups in Germany after World War II.
In order to control the church, Hitler commanded the union of all religious groups in Germany, drawing them together by law. The Brethren divided over this issue. Half accepted Hitler's dictum and half refused. The ones who submitted, of course, had a much easier time, but gradually in this organizational oneness with the liberal groups their own doctrinal sharpness and spiritual life withered. On the other hand, the group that stayed out remained spiritually virile, but there was hardly a family in which someone did not die in a German concentration camp.
Now can you imagine the emotional tension? The war is over, and these Christian brothers face each other again. They had the same doctrine and they had worked together for more than a generation. Now what is going to happen? One man remembers that his father died in a concentration camp and knows that these people over here remained safe. But people on the other side have deep personal feelings as well.
Then gradually these brothers came to know that this situation just would not do. A time was appointed when the elders of the two groups could meet together in a certain quiet place. I asked the man who told me this, "What did you do?" And he said, "Well, I'll tell you what we did. We came together, and we set aside several days in which each man would search his own heart." Here was a real difference; the emotions were deeply, deeply stirred. "My father has gone to the concentration camp; my mother was dragged away." These things are not just little pebbles on the beach; they reach into the deep well-springs of human emotions. But these people understood the command of Christ at this place, and for several days every man did nothing except search his own heart concerning his own failures and the commands of Christ. Then they met together.
I asked the man, "What happened then?"
And he said, "We just were one."
Timothy Lane, commenting on 1 Corinthians 12:1-11, writes: "Paul grounds our unity in the unity of the Trinity, not in our ability to get along. We get along because Father, Son, and Spirit have allowed us to do so. We can give grace because we have been given grace."