Every Sunday morning, the people of a church in the Pacific Northwest say, "Peace be with you." They begin the worship service with a hymn of praise. The people confess their sins together, and hear of God's forgiveness. Then they are invited to turn to others around them and pass the peace. It has become an exuberant moment in an otherwise sober occasion. Friends leave their pews to embrace one another. Newcomers are warmly welcomed with a kind word or a hug.

Nobody thought much about the weekly ritual until the pastor received a letter from a man who had r…