In the beginning when God created the heavens and the earth, the earth was a formless void and darkness covered the face of the deep, while a wind from God swept over the face of the waters.  
Genesis 1:1–2 

“Singing is considered a special act of respiration, and requires a motor plan. The role of respiratory function in singing is to provide a steady pressure head to generate sound.”   
R. T. Sataloff,  
Sataloff’s Comprehensive Textbook of Otolaryngology, Vol. 4 (2015)  

Lungs are designed to move mostly downwards. When the wall of muscle beneath them contracts, they are pulled down and the act of inspiration occurs — air enters the lungs through the nose or mouth, along with any aerosols that may be present. Then the air is exhaled with varying degrees of force — along with any aerosols that may be present.   

If you want to sing, though, an intermediate step must occur: the vocal folds must be made to vibrate at a consistent frequency. This happens mostly parasympathetically, but we do have some agency in keeping them in the right place and with the right amount of air to maintain vibration. The air, travelling from the lungs back out into the cosmos, meets a certain resistance.  

The ruach (Hebrew for the breath, the wind, the spirit)  is wild and untamed. It blows where it will. We are inspired as the Spirit desires. And yet, here is that wind (a gas) meeting cartilage (a solid) and that act of resistance might — just might — result in singing. The Spirit moves the air — along with any aerosols that may be present. 

Six feet. Twenty-seven feet. Cubic square feet. How much resistance is needed to make singing that can be heard at a safe distance? If I, the singer, do not exercise my abdominal core and my larynx with regular singing, the muscle tone weakens, and I cannot safely sing. Is the spirit, the wind, the breath safe? But I can sing by myself, alone, safely. Perhaps I can sing with a few others, very far apart, and masked, safely. And the Spirit will move the air — along with any aerosols that may be present. 

One deep calls to another in the noise of your cataracts; * 
    all your rapids and floods have gone over me.  
Psalm 42:7 (1979 Book of Common Prayer) 

“...Then two wonders happened at the same moment. One was that the voice was suddenly joined by other voices; more voices than you could possibly count. They were in harmony with it, but far higher up the scale: cold, tingling, silvery voices. The second wonder was that the blackness overhead, all at once, was blazing with stars...If you had seen and heard it...you would have felt quite certain that it was the stars themselves which were singing, and that it was the First Voice, the deep one, which had made them appear and made them sing.” 
C.S. Lewis, The Magician’s Nephew (1955) 

When a sound wave of a certain frequency comes into contact with a surface with the same natural frequency, we experience resonance. It happens in an empty stairwell, and it happens in our skulls. The breath comes in, the breath goes out and resists against the vocal folds, and frequencies are produced. They encounter the bones of the skull: the frontal bones, the occipital bones, the maxillo-facial bones, and their vibrations are amplified. The empty space of the sinus cavity resonates. It’s why a trained singer can sing in a huge hall with no microphone and be heard in the back row. That singer knows how to give life to the bones and use hard, empty spaces to propel the song.  

Vibrations can travel much farther than aerosols, and reach surfaces far away from our own skull. When they encounter stones, they bounce off those stones and move in different trajectories. And the molecules of the stones are enlivened by the vibrating wind, whose sound is begun in resistance and sent out by the bones.  

When two voices join at the same fundamental frequency or harmonically consistent, mathematically related frequencies, something magical happens. Tiny sub-vibrations, known as overtones, are set in motion and amplified by the combination of those frequencies. These give a richness, a brightness, ringing to the sound. The more vibrations that join in, the more overtones one experiences, making for a fuller, richer sound.  

Do the stones of buildings hold resonance? Do they hold the memories of what has been said and sung and screamed and moaned in them? Is that echo still there, outside of our range of hearing, but audible to the Creator of Vibrations? Are the stones crying out while we must be silent?  

Then he said to me, “Prophesy to the breath, prophesy, mortal, and say to the breath: Thus says the Lord God: Come from the four winds, O breath, and breathe upon these slain, that they may live.” I prophesied as he commanded me, and the breath came into them, and they lived, and stood on their feet, a vast multitude.   
Ezekiel 37:9–10 

Bone joined to bone, sinew to sinew, sound wave to sound wave.  

Prophesy to the bones, mortal. Prophesy to the cartilage of the vocal folds and the lungs. Prophecy to the aerosols, the stones. Prophesy, and say, “Mortal, can these songs live?” 

The Song exists apart from the singer, and apart from the listener. When we align our resistance with the Song’s vibration, we resonate with its frequency, and spread it throughout the earth. And we will be able to do that, soon, safely. Until then, the Song lives.