In A Light to the Nations, Michael Goheen explains the need to understand the nature of the Church (ecclesiology) in order to recover her missional role.
Ecclesiology is about understanding our identity, who we are, and why God has chosen us—whose we are. If we do not develop our self-understanding in terms of the role that we have been called to play in the biblical drama, we will find ourselves shaped by the idolatrous story in the dominant culture (5).
The foundation to the Church's identity is the victorious work of Jesus Christ. He has intruded a fallen world with the dominion of a new age, died for our sins, conquered death by his resurrection, and ascended to reign as King over all. This is good news and Jesus has commissioned the Church to be its herald.
Goheen gives five starting points in the gospel that lead us to discover what the Church is supposed to be (18-21).
First, "the gospel demands of its hearers that it be accepted as the real story of our world, the one event in history on which all the rest turns."
Second, the central theme of this story is "God's purpose and activity to renew the entire creation and the whole of human life."
Third, the central theme in the message of good news is the coming of the kingdom of God who through Jesus triumphs over sin, death, and evil.
Fourth, God works out his redemptive purposes by "choosing a people to make known to all where history is leading."
Fifth, "the gospel reveals that this community chosen and sent by Jesus is both the beginning of something new and the continuation of something much older."