When you were single you could avoid doing things you didn't want to do easily. If you're a guy, the things you avoided often might have included all the basic necessities to life: laundry, making meals, cleaning your living space, cleaning yourself, keeping a budget, and more. I'd imagine the reason God made our hearts beat involuntarily is because too many guys would procrastinate on that job.
When you got married, you began to realize doing the things you once avoided is now an act of love for someone else. You also started receiving requests by your spouse to do all sorts of things you used to avoid. If you've been married for any length of time you've probably been asked to go grocery shopping, fold the laundry, clean the bathrooms, and take a shower. It is safe to say that, "Sure, honey!" should be your loving response most of the time. But you know, and your wife really knows, that is not the response you always want to give.
Looking at transcripts of these moments with your wife, if you responded with "Sure, honey!" every single time you were asked to do something you did not want to do you would seem like a very loving husband. One of the best. But you're wife might know a totally different story; the story of your tone.
We all know, "Sure, honey!" can communicate, "Absolutely. I have no problem doing that. I love you. It's a privilege to serve you and our family." We also know it can communicate, "That is the last thing I want to do and I want you to know that it is the last thing I want to do, but I will fall in line like a 'good' husband and do it." What makes the difference between these two messages? Tone.
Tone is the difference. Tone communicates the complete message. And this is no different when it comes to preaching. Listeners automatically, without trying, analyze the tone of a preacher. Though listeners may not remember a single thing you said, they still might remember that you sounded angry, happy, or frustrated. This can be a great thing for your preaching or a terrible thing for your preaching.
It can be a great thing because your tone can bolster and emphasize your content. If you are preaching about the joy of our salvation in Christ and you sound happy, listeners lend you credibility. You sound like you really believe what you are preaching. It is real to you and your tone reveals that. In this way, tone is your best friend. Your tone can say, "This stuff is true! I believe it! You should believe it with me!"
Tone can also be the downfall of your sermon. Tone can reveal what you really believe. Tone can reveal two devastating things for your preaching ministry: you are not moved by what you preach and you do not love your listeners.
What happens when listeners hear, in your tone, that you seem unmoved by your content? As listeners, they may conclude that if the preacher is unmoved, why should they be moved? If he seems to lack conviction, why should they be convicted? If he lacks joy, why should they have joy? Tone can strip credibility from a preacher. Of course, on the flip side, a preacher could admit, "I confess, I'm not moved by these truths! I need grace!" Doing so would be powerful and lend credibility to the preacher. It is when a preacher seems to not realize his tone betrays him that his message will be received poorly.
What happens when listeners hear, in your tone, that you do not love them? As listeners, they simply won't want to listen to you! Who wants to listen to someone preach at them for 30-60 minutes if that preacher does not love them? Why would I want to listen to someone who sounds like they hate me? Why would I want to listen to someone who seems perpetually frustrated with me, though I can't think of an obvious reason why? This is what listeners will feel when your tone says you do not like your listeners.
Perhaps the greatest way to ensure your tone will help your preaching is to let the biblical material you are preaching sink deep in your bones and let your listeners lodge deep in your heart. Pray your text moves you, convicts you, and, ultimately, cheers your heart as you see the whole Bible pointing to Christ crucified. As you do this, remember why you preach: to help those who hear. You preach not for fame, but to help everyone who comes into your church exhausted and limping. They need grace. They need Christ. You are there to deliver the Good News that He loves them, was crucified for them, and is present for them. May your tone bolster that reality.