Many years ago in their book Resident Aliens, Stanley Hauerwas and William Willimon contrasted the theological agendas of Paul Tillich and Karl Barth.
Tillich (along with Bultmann) assumed in his work that Christianity in its traditional form was a problem for the modern world. Thus he embarked on a theology of translation in which the ancient metaphors and symbols could be "translated" (Bultmann; demythologize) into language and ideas that could be believed in the twentieth century. Hauerwas and Willimon reject such a project. They write,
Thus instead of the gospel transforming the world, the gospel becomes transformed by the world; it conforms to our expectation and our sensibilities, rather than the other way around.
Hauerwas and Willimon then contrast Tillich's theological approach with that of Karl Barth, who understood that the task of theological inquiry was not to present the gospel in modern terms that made sense (which makes the Good News quite status quo), but rather to change, to transform lives after the character of Jesus Christ (p. 28). In other words, Tillich thought that the gospel had to be made credible to the modern world; Barth rightly understood that the world needed to be made credible to the gospel (p. 24).
What does this have to do with preaching? Absolutely everything! Any preacher who starts with the premise of making her or his sermon relevant will fail to preach the gospel. The gospel of Jesus Christ does not need to be made relevant; it is relevant. It is relevant to every age and every place. There is nothing the modern preacher needs to do to bring the gospel into the twenty-first century. It is not the modern world that stands in judgment over the gospel; it is the gospel that stands in judgment over the modern world.
Being a preacher, I have not heard too many sermons over the years, but on the few occasions that I have, I cringe when the preacher standing in the pulpit of the church talks about "the real world out there," as if what happens in the church is not the real world. It is the conviction of the New Testament that the real world is not "out there;" the real world is to be found in the church, the earthly embodiment of God's Kingdom. The world "out there" is not the real world God wanted in the first place. It is a world distorted because of sin. The church is to model for the world "out there" the reality of what God wants it to become.
There is nothing wrong with the church wanting to be "contemporary" (whatever that means) in respect to how the message is communicated through the use of current technology and music (etc.). Indeed, I believe that such considerations in reference to media are absolutely essential. But the substance of the message does not need to be changed to conform to current sensibilities. Those preachers who attempt to do so will be proclaiming something other than the gospel of Jesus Christ, and they will mislead those who hear.
Translation preaching removes the scandal of the gospel offering the Good News as simply one more form of therapy, or as merely one way to God among all the others, thereby stripping the cross of its saving power. Good preachers will not seek to be relevant, but to proclaim the already relevant gospel to their congregations. We must never forget, as Bishop Willimon reminds us elsewhere, that during his ministry Jesus drove away as many people as he attracted. While we want our preaching to attract everyone, we cannot compromise the gospel because it may drive others away. If we do that, we may not have people rejecting what we say, but we will find that people are no longer interested, because we will not be offering to the world anything that they cannot get elsewhere. Preachers must preach in a way that those who hear them will say, "I cannot get this anywhere else." Preaching that intentionally seeks to be relevant will become irrelevant.