Very readable edition of this volume of selected sermons preached by Jonathan Edwards to his congregation in 18th C America.
What always strikes me about Edward's sermons (and more so with earlier Puritans) is that these are actual sermons preached to their congregations. Not only are they incredibly lengthy but they are also theogically rich, deep, and so closely reasoned. They required enormous concentration by those listening, most of whom were not academics but ordinary locals - farmers, labourers etc. And yet today in our churches we have no end of graduate professionals, and PhD's in our congregations who regard a 40 minute sermon as quite demanding (although thankfully things have improved in this regard in recent years in evangelicalism).
Some would argue that times have changed, with the advent of modern media and people being raised on TV, video, and social media soundbites. And that this affects not only their concentration span, but also their ability to think conceptually. The argument is that today, preaching must be in concrete rather than conceptual terms. But this is really is a complete myth, and a failure to reckon with the doctrine of man.
The reality is that every human being is made in the image of God. And an aspect of being made in God's image is the capacity to think logically and to reason. It is the job of the preacher to teach his congregation to think and listen logically. We do them an immense disservice by dumbing down the preaching. And we insult their intelligence. (By the way, this is not a "class" thing but a theological thing).
But at the same time, let me add, that no, preaching must never be boring. To preach the word of God (!) - the word of God - in a way as to be boring, is frankly criminal.