One can know the depth of self through the experience of knowing the movement of energy with the body. The experience emerges from sound subtleness of body that vibrate to the energy emitted through the power of consciousness that is connected at the body, mind and spirit level. This is the power of sound and every single syllable that is contained in the nature allow one to go deeper through the essence of spirit that rises from the subtlety of the sound itself. The one single syllable that allows one to connect to the inner consciousness becomes a mantra for the seeker.
It is this mantra that keeps on rising and expanding till it connects to consciousness at all levels of the energy and matter.