Since the 3rd or 4th Century B.C., in some parts of this world, the symbol of OM and it's associated sound, pronounced AUM, were considered sacred. Its use began as a fundamental exercise within the science of yoga. How does a person gain some benefit by repetitively intonating OM? It is a way to raise the energy of the body from the pelvic region to the brain so that spiritual energy, hidden within us, can flood and then open brain centers as they receive more energy. The proper way to enunciate this is by using a deep tone/low vibration to begin when the A is pronounced, which matches the low frequency of the pelvic area, then gradually raise the pitch until it's as high as you can create to resonate in the cranium. The continued sound production should take several seconds, and with frequent repetition can induce a connection between your unconscious and conscious minds. As you intonate the deeper sound of A to stimulate the 1st chakra, keep your mind on the lower part of the pelvic area, feel that deep sound vibrate there, and then as you transition to the sound of the U, pass through the second lower abdominal chakra and the third upper abdominal chakra in the stomach area, keeping your mind focused on these areas and feel the sound vibrate there as it passes through those points. Then use the transition to the M sound as you feel that sound energy passing through the heart and throat chakras, and then use the final M sounds at the highest frequencies to get through the sixth forehead chakra and then the seventh crown chakra at the top of the head. In this way, you can assist the reunification of your conscious and unconscious minds. Recall that God also has a conscious mind, but our Paradox 6 states that God's conscious mind is it's creations, so when enhancing the connection between our conscious and unconscious minds, we assist God's conscious development.
Lately, recognition of the importance of the vagus nerve has become popular. The vagus is the main communication conduit between brain centers and the abdominal viscera. Intonating OM stimulates the vagus nerve as it passes superficially down through the throat area, thereby facilitating the brain/viscera, No. Pole vs. So. Pole, conscious and unconscious unification. This action is an important part of raising kundalini energy, when the entire consciousness can function once again as one. Here's an interesting aspect: when the poles begin to unite there can be flashes of light leading to a cascade of light streaming through the consciousness, which is the beginning of spiritual enlightenment. OM can be an important part of initiating this process.