As a seminary intern in St. Louis, Missouri, I was part of a Jewish-Christian Dialogue group. We were seeking to understand one another's traditions, work together for the good of our neighborhoods, and promote tolerance and respect in society. I had been invited into the group by a member of the church at which I was serving. She grew up Jewish, and in recent years had, in her words, "completed my faith" by gaining an understanding that Jesus is the Messiah foretold by the prophets of Israel.

One of the dimensions of religious life that we all found we had in common across faith traditions and denominational lines was the incessant divisiveness that split our seemingly monolithic communities into dozens of similar yet tenaciously varied subgroups. A Jewish professor of psychology said of…