Long volumes by some of Christianity’s most gifted thinkers and writers have been offered attempting an answer to this question. It is simply the ethical question, that is, the question of what it means to live rightly in the world. Of course, different faith traditions and confessions within Christianity have offered diametrically divergent answers to this question. H. Richard Niebuhr made this abundantly clear when he published Christ and Culture in 1950. Some would say that the duty of Christians is to reject and retreat from the dark and godless world mired in sin and ruled by Satan. Others would urge Christians actively to cooperate with the objectives and aspirations of the world, convinced that God is working in the world to fulfill his purposes through virtually all institutions. Other groups of believers, of course, would fall between these polar extremes. Aware of the breadth and complexity of this continuing conversation and with deference to the stature and wisdom of the array of witnesses who have proceeded me, I will echo a faithful group of these witnesses and suggest a two-pronged responsibility, one aimed at a temporal goal, the other a spiritual goal.
The Christian who by faith knows the grace given her through the life, death, and resurrection of Jesus Christ and then delivered through God’s chosen means, also recognizes that God has worked to redeem and sanctify her precisely so that she may accomplish what he created her to do. She is justified so that she may live a life of service to those around her in the reality of this temporal world. This life of service for the sake of others is carried out specifically through the peculiar vocations that have been given to her. The believer is responsible to use the gifts, skills, talents, and resources given to her to care for those around her and to bring God’s justice more fully to bear on the operations of this world. That’s the first aspect of the twofold responsibility. The second is closely related but aimed directly at what might be called the spiritual (in contrast to the temporal) objective of witnessing boldly to the reality of the God’s truth fully revealed in the incarnate Son. The believer serves through her vocations, and then with deliberation seizes opportunities that arise to speak of God’s truth and love to those who will listen. She witnesses the reality of Christ’s gospel through her life and with her words. This consistent and faithful witness in her life (meeting temporal needs) and in her words (speaking spiritual realities) are the heart of a Christian’s responsibility toward the world.
Joel D. Biermann, Ph.D. is the Waldemar A. and June Schuette Professor of Systematic Theology at Concordia Seminary, St. Louis.
For Professor Biermann's full treatment of this question:
Biermann, Joel, Wholly Citizens: God's Two Realms and Christian Engagement with the World