I came across this somewhat at random, but it illustrates a point. In an article on the role of theology on the Gordon Conwell website John Jefferson argues that a sound biblical theology is like the backbone in the human body—it provides “support, shape and stability to the Body of Christ”.
In the early church this was expressed through four functions: catechesis, or the teaching of basic Christian doctrine; apologetics, the defence of the faith; polemics, the suppression of heresy; and homiletics—“assisting preachers and teachers in the exposition and teaching of Scripture”.
Jefferson then goes on to suggest that a sound biblical theology “can provide vitality, vision and standards for assessment in the local congregation”. The framework for vision is provided by the “biblical metanarrative of creation, fall, redemption and new creation”, and the point is made that salvation is not just about forgiveness of sins and the hope of heaven but also about an “experience beginning now of entering into the life of the Triune God”.