"Over the years, I've heard some wonderful sermons," writes G. Robert Jacks. "I've also heard some duds. Some have been so extemporaneous they sounded as if the preacher hadn't prepared anything. Some have been such wondrously crafted literary pieces they sounded as if the preacher wanted to sound wondrously crafted and literary. Some have sounded as though the preacher were giving a lecture or reading a term paper. That's because the preacher had...