In spite of what many people think, the sermon is not the most important item in a church service. We are there to worship God and the sermon is part of that.
The poet T.S.Eliot wrote:
... You are not here to verify,
Instruct yourself, or inform curiosity
Or carry report. You are here to kneel
Where prayer has been valid.
(from The Four Quartets)
A sermon is part of the process of coming nearer to God in worship. The words we use in our church services are not like the words in a lecture or a handbook. They are part of our conversation with the living God. This conversation has been going on through the whole of the Church's history (if not before) and engages us all.
It is not the preacher's primary task to give the congregation hints or something to make them feel better in the coming week. Still less is it to bolster their sense of righteousness by going on about the faults of others. A sermon may well contain illustrations from everyday life or refer to things in the news but it is not intended to give specific applications of the day's Bible readings. Most of the Bible is not intended for that purpose anyway.
People who preach have the joy and privilege of sharing something of what God is saying to them, of where they are in their walk with God, and of preparing the congregation for their encounter with him at the altar.
If the sermon gives the congregation "new thoughts of God, new hopes of heaven" (to quote another poet, George Herbert), then the preacher has done his duty.
PMP