Mark Dever offers why theology is critical in how you “do” church:
Are people basically bad or good? That will determine much of what you think a church needs to do. If you think people are basically good, then a church is a simply a place where we seek encouragement or perhaps the enhancement of our self-esteem. We need simply to take the good that’s in us and build on it. However, if you think something is much more radically wrong with us humans, if you think that we are spiritually dead, guilty before God and separated from him, then there is something different that churches must do. In that case, churches need to present the Gospel clearly. Churches need to tell people how to find forgiveness for their sins and how to find new life. We will “do church” differently, depending on how we understand God and ourselves. To be biblical, we must know that God is a holy God and that we, by nature, are dead in our sins and transgression and justly stand under His condemnation [Nine Marks of a Healthy Church (Wheaton: Crossway Books, 2004), 66].