Okay, I’m going to talk about physics. Someone guard the doors — nobody leaves!

This is Good Shepherd Sunday, when we always get Jesus using imagery of sheep and shepherds. This morning Jesus addresses the crowd that has already tried to kill him once and will again in just a minute, and he says, "You do not believe because you do not belong to my sheep. My sheep hear my voice. I know them, and they follow me." He’s alluding to a wonderful custom of shepherds singing to their sheep. The shepherds would all bring their flocks to a watering hole. Hundreds of sheep would intermingle while, I imagine, the shepherds sat in the shade and chewed the fat. When it was time for a shepherd to leave, he would call his sheep, usually singing to them, and they would know his voice and his tune and come to him.

"My sheep hear my voice," Jesus says. "I know them, and they follow me." Now we all know that we are supposed to identify with those sheep, but I hope we all know that we aren’t actually sheep, which is a good thing because sheep are stupid and they stink to high heaven. And not only that, but we don’t actually get to hear Jesus’ voice. Maybe some of you have literally heard the voice of God (I’m not disputing that), but you have to admit that in the day to day conduct of our lives, most of us don’t literally get to hear Jesus’ voice. I’m sorry about that; I’d like to know what he sounded like.

So, we’re supposed to identify with sheep, but we’re not sheep (thank God), and we’re supposed to listen, but we’re supposed to listen for a voice that, for most of us, is rarely, if ever, spoken.

I don’t have auditory experiences of God; I don’t literally hear Jesus’ voice, so I have to understand listening for what Christ is saying metaphorically, and what I find useful in that regard is to think about Christ’s voice resonating within me. That kind of takes my ears out of the equation. You resonate with all of your being.

Here’s where the physics comes in. When something resonates, it means that it vibrates in response to a force acting on it. It’s going to vibrate at a frequency that is determined by it’s shape and mass and probably lots of other things I don’t know about. That frequency is called its resonant frequency. If you wet your finger and run it around the rim of a crystal glass, it will sing a note that is its resonant frequency. Add a little water to the glass, the note will change.

Now, it really gets interesting when you have another object nearby which has the same resonant frequency of the thing being vibrated. (Stay with me now.) For example, if you have another wine glass, just the same as the first so it has the same resonant frequency, when you make the first glass sing, the second glass will respond and begin to sing too. (You’ll be able to tell because the sound will get louder.) And the more you make the first glass sing, the louder the second will sing. This is how opera singers shatter wine glasses — they hit a note at the exact resonance frequency of the wine glass and hold it until the glass vibrates itself apart.

Now, a little demonstration. [I struck a tuning fork and placed it over a beaker with water in it. Nothing happened because the tuning fork and the beaker had different resonant frequencies. Then I did it again using a different fork with the same resonance frequency as the beaker. The note, which was barely audible from the fork alone, was very noticeably amplified so that everyone could hear it. I then changed the beaker by adding water. Now nothing happened when the fork was placed over the beaker. ]

There’s another experiment you can do in Bott Hall. Sing a note into the back of the piano. All the strings will be silent except one. One string will recognize the note that is somehow, mysteriously, tuned to its being, and it will vibrate and sing that note back to you.

Okay, are you with me on this? Do you understand resonant frequencies?

All that’s pretty interesting, but what does it have to do with us. Well, we are created in the image of God. That is a powerful and mysterious statement, and I’m not sure we ever finish learning what it means. But one of the things I think it means is that we were created to be tuned to God’s voice. We were created to have a resonant frequency that makes our very being vibrate when we hear the love song Christ sings to us, so that we can sing that song back just like that beaker with water in it sang that note back to the tuning fork.

That, I believe, is how we were created. But God has given us the free will to be able to add water, take water out, change our frequencies, vibrate with different notes, respond to different songs, different voices. So I want to ask you to think with me about how we have changed our tuning. What vibrations have we tuned ourselves to hear and to respond to? The call of money? The call of youth? Sex? Fear of dying? Alcohol? Drugs? Nicotine? Anxiety? Prestige? Success? Recognition? Expensive toys? Family? Being right? Have we tuned those things in? Do we resonate to any of them?

Have we tuned out God’s call to recognize the gifts God has given us and to use them in response? Do we resonate to that? Have we tuned out God’s call to dedicate our lives to God, with every bit of our being resonating to that call?

I doubt there is one of us who has not changed our tuning somehow. I certainly have. Maybe during this Easter season, as we’re hearing the constant song of our Shepherd, the joyful refrain of alleluias, maybe we can work a bit on re-tuning ourselves. I think we do that through time for prayer. I think we re-tune ourselves by examining what makes us respond, what we are tuned to. I think we re-tune by listening to the poetry of the liturgy and the power of the story it tells with not just our ears, but our being. I think we re-tune by claiming our Christianity proudly in the world, and by proclaiming it proudly to the world. I think we re-tune by reading Scripture as God’s love song. I think we re-tune by being in the community of faith and letting it shape us. I think we re-tune by serving others in Christ’s name.

My guess is that we could all use some practice changing our resonant frequencies, tuning our beings, so that when our shepherd, the King of love, calls us, we may respond to that pure note with a pure note of our own. Actually, I think that is a lifetime quest. But let’s get started now. See if you know how to respond to this:

"Alleluia, Christ is risen."