In A Scottish Christian Heritage Iain Murray has this to say about preaching that is worthy to be called such:

True preaching, according to the New Testament, does not mean simply hearing about Christ, it is hearing Christ himself: it is Christ speaking, Christ inviting, Christ calling to repentance. The preacher is present only as a messenger; Christ is present to be believed, to be obeyed and to be worshipped. Where preaching does not lead to that, and only begins and ends with the sermon, it has failed (332, emphasis in the original).

I think Murray has in mind passages such as Ephesians 2:17.

And he [that is, Christ] came and preached [through his messengers] peace to you who were far off and peace to those who were near (ESV).

Comments, thoughts, questions?