Read what Carl Trueman writes about Luther’s theology of preaching and how it applies today:
From childhood upward, we are told that we are special. Sometimes this is even done in God’s name. The televangelists and megachurch pastors who talk about having “your best life now” are essentially presenting a picture of God as one who panders to the particular needs and concerns of the individual. The danger is that preaching can start to do the same–even worse, that preaching becomes sidelined because each person has to have his or her particular needs and problems addressed in a specific fashion.
Luther’s approach to preaching is a refreshing riposte to this kind of narcissistic nonsense in at least two ways. First, his application of the categories of law and gospel in his sermons captures on crucial truth: human beings, for all their uniqueness, are not unique in term of their status before God. There are only two ways of approaching God: by law or by gospel. And there are only two things one can say about any human being before God: a person is under wrath or under grace. While individuals have their own histories and circumstances, their own problems and challenges, the basic problem of where to find a gracious God is the same for all, as is the answer.
Second, Luther’s theology of preaching reminds us that the Word has power in itself because it is the Word of God. Luther understood both law and gospel as possessing moral force. They expose the heart of the theologian in everyone, of course, showing every human being to be a theologian either of glory or of the cross.
And in conclusion:
Thus, Luther’s theology of the Word and preaching stands at the center of the Christian life. There in the sermon, in the move from law to gospel, the fundamental struggle of the Christian is played out every time the preached ascends the pulpit. But this is no mere theatrical display: as the Word is preached, the Christian is torn down by the law and built up in the gospel. Preaching is a supernatural act, and that should give great confidence and assurance to every preacher tasked with the public exposition of God’s Word.
–Carl R. Trueman, Luther on the Christian Life (Wheaton, Ill: Crossway, 2015), 96-97