First, D.A. Carson (from an excellent talk on the gospel and social action) on how the whole Bible hangs together and how preachers need to demonstrate that:
Every sermon based on any biblical text needs to be integrated into the theme of the book in question, which needs to be integrated into the canon, which inevitably brings you in one fashion or another to the centrality of Christ. It just does. . . . Expository preaching is not only explaining what a text says in its bitty [garbled audio], but faithful expository preaching is also showing from that "bitty" text, its inter-canonical connections to the great tendons that run right through Scripture to bring you the centrality of Jesus. That makes for powerful worldview-ish preaching.Second, Spurgeon: Preach Christ or go home. (A raft of great quotes here.)
And finally, a useful webinar video from two of my SEBTS profs on what people mean by a gospel-centered life.
To accept the sufficiency of the gospel doesn't just mean that the gospel is enough to get you to heaven. What it means is that for our churches, the gospel is the only thing we need. I mean, it really is enough. We have fallen victim to this idea that the gospel is not enough to reach people, and to see people grow. And as a consequence we've come up with all sorts of schemes and gimmicks and plans that actually are contrary to the gospel because they all become a way for us to trick people to become church members. If our goal is to make church member, then we are not on board with God. The goal is to make disciples. That's the Great Commission. What happens though, sadly, is that we're like the Pharisees. We'll travel 100 miles and beat on a thousand doors . . . in order to make a church member. And in the end we make them twice the son of hell that we are. The goal is to make disciples.