I remember Haddon Robinson saying that a mist in the pulpit will result in a fog in the pew. It seems so obvious to say it, but there is a strong connection between what is going on in the preacher and what will go on in the listeners. This is true both positively and negatively. Here are some examples with brief comment:
1. Nerves & Stress. If you are nervous, they will join you in that. If you seem stressed, you will put them on edge. Whatever your preparation has or has not been like, make sure you go into preaching by faith rather than self-reliance, or self-concerned stress.
2. Coldness & Distance. A congregation is like a dog in this regard: they can always sense if you don’t care for them. Pray until your heart beats with God’s heart for these people, especially when you sense that indifference and lack of love that so easily creeps in for all of us.
3. Boredom & Disinterest. Nobody wants to listen to someone who is not particularly interested in the passage they are preaching or the God they are speaking about. In fact, they won’t listen. Your disinterest will transmit so that they mentally leave the venue long before you leave the pulpit.
4. Warmth & Connection. Maybe you have met somebody so warm and congenial that you found yourself warming to them as the conversation progressed. The same is true in preaching: your love for them and enthusiasm for the God you speak about will increase their temperature toward you and Him!
5. Clarity of Image. Whether it is an illustration or the retelling of a narrative, this principle applies: if you can see it, so will they. Be prepared enough to be able to see what you are describing and you will be surprised how much more your listeners feel like they are immersed in the movie, not just enduring a monologue. Blow the fog away, describe what is vivid to your mind and it will be clear to theirs, and engaging to their hearts too.
6. Responsiveness & Worship. This goes way beyond enthusiasm and even interpersonal warmth. This is about response to God. If you are moved by the passage and the message to worship and obedience birthed from stirred affection, then that will increasingly be the response of your listeners too.
There are many ways in which we will infect our listeners as we preach. What “diseases” do we want to carry to them?