We never “get beyond the gospel” in our Christian life to something more “advanced.” The gospel is not the first “step” in a “stairway” of truths, rather, it is more like the “hub” in a “wheel” of truth. The gospel is not just the A-B-C’s of Christianity, but it is the A to Z of Christianity. The gospel is not just the minimum required doctrine necessary to enter the kingdom, but the way we all make progress in the kingdom. We are not justified by the gospel and then sanctified by obedience but the gospel is the we grow (Gal. 3:1-3) and are renewed (Col 1:6). It is the solution to each problem, the key to each closed door, the power through every barrier (Rom 1:16-17).
It is very common in the church to think as follows: “The gospel is for non-Christians. One needs it to be saved. But once saved, you grow through hard work and obedience.” But Colossians 1:6 shows that this is a mistake. Both confession and “hard work” that is not arising from and “in line” with the gospel will not sanctify you—it will strangle you. All our problems come from a failure to apply the gospel. Thus when Paul left the Ephesians he committed them “to the word of his grace, which can build you up” (Acts 20:32).
The main problem, then, in the Christian life is that we have not thought out the deep implications of the gospel, we have not “used” the gospel in and on all parts of our life. Richard Lovelace says that most people’s problems are just a failure to be oriented to the gospel—a failure to grasp and believe it through and through. Luther says (on Gal. 2:14), “The truth of the Gospel is the principle article of all Christian doctrine… Most necessary is it that we know this article well, teach it to others, and beat it into their heads continually.” The gospel is not easily comprehended. Paul says that the gospel only does its renewing work in us as we understand it in all its truth. All of us, to some degree live around the truth of the gospel but do new “get” it. So the key to continual and deeper spiritual renewal and revival is the continual re-discovery of the gospel. A stage of renewal is always the discovery of a new implication or application of the gospel—seeing more of its truth. This is true for either an individual or a church.
Keller on the Gospel
Here is Tim Keller on the gospel. (I got this from Justin Taylor, who got it from the Resurgence site, who got it from the Desiring God audio of Keller's message at the last DG conference.) This is typical of Keller's gospel-laced "theologizing" (to use his word). I love it. Read, learn, grow, enjoy.