I must confess at this point that I belong to the old reactionary tendency which regards the man who cannot preach in an interesting and informative manner as simply not called to the preaching ministry. IF a man mounts a pulpit and cannot set his people’s heart on fire for the Bible, then he had better not step into the pulpit at all, for to put Christians off hearing and reading the Word of God has to be one of the most serious acts one can commit.
Carl Trueman, Reformation: Yesterday, Today, and Tomorrow
Spurgeon had this to say about bad preaching,
If some men were sentenced to hear their own sermons, it would be a righteous judgment upon them; but they would soon cry out with Cain, “My punishment is greater than I can bear.”