John C. Purdy, a staff member of the Presbyterian Church U.S.A., has written a challenging book entitled Returning God's Call: The Challenge of Christian Living. In it, Purdy suggests that we need a new metaphor for the Christian life. He points out the inadequacy of the old metaphors such as "a soldier in God's army," "a scholar in the school of Christ," "a traveler a long the Christian way," "a citizen of the commonwealth; "and a member of Christ's body." Each of these metaphors has served us well in the past, Purdy says, but they are not as useful for today. The metaphor Purdy recommends with much vitality is "Hearers of the Call." His rationale is that this would be the image of one who has heard, and keeps hearing, a persistent summons to belief and action. "Hearers of the Call!" Whet…