The Doctrine of Depravity and Preaching

The principal mark of the three that distinguish the faithful and true church of Jesus Christ is the pure preaching of the gospel. Proper preaching is not to be equated with making speeches or being eloquent. Proper preaching of the gospel is to be distinguished by the content of that which is presented. What must the preaching of the gospel proclaim? And where does a doctrine such as "total depravity" fit within this preaching of the gospel? Some might insist that it has no place in the...