Taken from pages 106-108:
God's shepherds are called to keep watch over God's flock. But of all the things that need to be watched, the one that was of greatest concern to the apostle Paul was the church's theology. Indeed, this is one of his major concerns throughout his writings. Few things were more important to him than preserving sound doctrine.
Doctrinal error that leads a church astray almost never arises from the laity, but nearly always comes from the clergy. One of the most likely places for heresy to originate is from the church pulpit or the seminary lectern.
If that is true, then how can the church protect itself from theological error? It is up to the elders - the shepherds of God's flock - who are called to keep watch over the church in doctrine as well as in life. Proper oversight is essential to the moral and doctrinal health of the church.
This is why it is so important for pastors and elders to study theology. In order for a congregation to have any hope of preserving its doctrinal purity, its pastors and elders must be defenders of the faith.
Protecting and promoting sound doctrine is a matter of spiritual health. Theology is important, not simply for its own sake, but because its corruption inevitably causes spiritual damage in the lives of individual Christians.
Ultimately, it is for the sake of their sheep that the shepherds of God's flock keep careful watch over the church's doctrine.