You can have good preaching even with a poor sermon; it is a real possibility. ... There is the sermon, a sermon which he has prepared; and then there is the 'act' of delivering this sermon. Another way of stating it is this. A man came -- I think it was actually in Philadelphia -- on one occasion to the great George Whitefield and asked if he might print his sermons. Whitefield gave this reply; he said, 'Well, I have no inherent objection, if you like, but you will never be able to put on the printed page the lightning and the thunder.' That is the distinction -- the sermon, and the 'lightning and the thunder'. To Whitefield this was of very great importance, and it should be of very great importance to all preachers... You can put the sermon into print, but not the lightning and the thunder. That comes into the act of preaching and cannot be conveyed by cold print. Indeed it almost baffles the descriptive powers of the best reporters.
D. Martyn Lloyd-Jones, Preaching and Preachers, pf 58.
From Dr. Keller's latest blog post "Lloyd-Jones on the Practice of Real Preaching"...
I would argue that in a post-Christian culture, preaching will not be effective in the gathered assembly if Christians are not also highly effective in their scattered state. In our times, people will be indifferent or hostile to the idea of attending church services without positive contact with Christians living out their lives in love and service. Therefore the incarnational "dispersed" ministry of the church is extremely vital and necessary.
Here's a snippit from Tim Keller's blog post today: Lloyd-Jones on the Primacy of Preaching...
Dr. Lloyd-Jones effectively dismantles the idea that watching a video or listening to an audio of a sermon is as good as coming physically into an assembly and listening to a sermon with a body of people. It is obviously a good thing if a person who never hears or reads the Bible listens to the recording of a good gospel message and is helped by it. But the Doctor argues that people experience the sermon in a radically different way if they hear it together with a body of listeners and if they see the preacher. Watching on a screen or listening as you walk detaches you and the sermon becomes mere information, not a whole experience. There is a power and impact that the media cannot convey.