I know this might be a boring subject for some, but I love this quote I just read from Karl Barth (a theologian in Germany during the first half of the 20th century.)
“No matter what may be said in detail, this is the point from which every single line of preaching must be drawn: not the mere word Christ, not the mere description of Christ, but solely what God has done with us in Christ. Emmanuel—God with us—this is the central point in all preaching. Only when this is the message for delivery, does the preacher speak with the full authority of the one who sends the herald.”