Joel R. Beeke discusses the three important elements of a good sermon. For both listeners and preachers, a good sermon should be idealistic, realistic, and optimistic.
The Psalms present the idealistic, realistic, and optimistic view of the Christian life...a preacher must do that as well. If you only preach the idealistic, the Romans 8 part, where everything is well and you're growing in the Spirit; you're being conformed to the image of Christ; the love of Christ is very real and vibrant in your heart; you know nothing will separate you from the love of Christ; this is wonderfully idealistic. If you only do that, and you don't talk about the realistic part of struggling with sin, the Romans 7 part, then what will happen is those beleaguered believers who really wrestle with sinning in your midst are going to say, "I don't think I'm even saved. I mean, I just can't live up to that, the bar is way too high." If you only preach the realistic part and you don't preach the idealistic part, then the believer is going to say, "oh, I've arrived there's nothing more for me to do. This is, you know, this tug of war with sin, this is going on in me all the time. I love what the preacher is saying, I can identify with it. But if the preacher doesn't hold up the idealistic part, you see, then the believer isn't stretching out, he's not doing what Paul said, "I forget the things that lay behind and I press forward towards the high prize of the calling of God." He's not seeking to grow in holiness.
Listen below to the rest of Dr. Beeke's discussion of what a good sermon should be like.
Content based on Reformed Preaching: Proclaiming God's Word from the Heart of the Preacher to the Heart of His People by Joel R. Beeke. Used with permission Crossway.org.