What is sound? Is it a physical wave motion or is it a perception? Sound can be defined as a longitudinal wave-energy traveling through a medium. However, hearing is a complex process in which that sound wave is converted to a sound. First, the wave-energy is transferred to a vibrating membrane called the ear drum; the vibrating drum causes the movement of three articulated bones called the hammer, anvil, and stirrup; these bones cause a vibration in the fluid-filled cochlea of the inner ear; the cochlea is lined with thousands of fine cellular hairs called cilia, and each cilium is designed to react to a certain frequency; as these cilia pick up their individual frequencies, they stimulate the nerve fibers of the auditory nerve to produce a complicated electrical impulse; this impulse is carried by the auditory nerve to the occipital area of the brain where it is converted into an electrochemical response called sound. Any interruption of this complicated path results in partial or even total deafness.
Impaired hearing has become so common that a special medical technology has been developed to meet the challenge. Remedies to hearing impairment may require a hearing aid, which amplifies the sound; bone transmission can bypass a middle ear problem; and even cochlear implants can correct inner ear problems. However, if there is damage to the auditory nerve or brain, there is little that can be done. We have all experienced the psychological aspect of hearing. My wife accuses me of not listening to her. She is producing a sound wave, she is moving her lips to articulate words, but since my attention and thinking is elsewhere, even though my hearing is fairly normal, which she doubts, I do not hear her. When I taught school, the hum of a classroom full of chatty students hardly registered on my consciousness, but any unusual noise or commotion alerted my attention. We can "turn off" our hearing; the ear may be receiving the sound and transmitting it by the auditory nerve to the brain, but there is no mental impression.
The Bible talks about this type of hearing loss. We are told about ears that hear not and eyes that see not (Mark 8:18). We are counseled that we should listen to what the Spirit says to the churches (Rev. 3:22). This admonition is repeated for each one of the seven churches, so it must be important. The Spirit tells the Ephesians that they need to renew their first love; He tells the Smyrnans to remember the reward for their suffering; He tells the Pergamons not to be misled by false teachings; He tells the Thyratirans not to be deceived by false prophets; He tells the Sardinians to wake up; He tells the Philadelphians to turn from sin; and He tells the Laodiceans to warm up or chill out. Each admonition ends with the promise that those who are victorious will sit on God's throne. The words of the Spirit to the churches apply to all of us. The Spirit is speaking to you, "are you listening?"
