The Sanskrit word nada means ‘to flow’. In this context it means a ‘flow of consciousness’. The word is closely related to the word nadi, which means a pathway of pranic flow within the human framework. Generally the word nada is understood as sound, for it is the inner sound that is used as a focal point of awareness in retracing the flow of consciousness back to the source.
There are countless references to nada in ancient scriptures throughout the world. Of the Indian texts, it is fully discussed in the following: Nada Bindu Upanishad, Dhyana Bindu Upanishad, Shiva Mahapuranam, Hatha Yoga Pradipika, Yoga Taravali, Gherand Samhita, Granth Sahib and many more. The following quotations are merely a selection:
those of the ocean, clouds … ” Nada Bindu Upanishad
“Nam (nada) is the true nectar (divine bliss), but nothing can be said about it. Only he who merges with it can drink and know this nectar.” “In the same way that the fragrance is in the flower and a reflection is in a mirror, so the nam (nada) is within you. Seek it in your own being.” Granth Sahib
It was Kabir who said: “The nada is within. It is music without strings played within the body. It pervades inside and outside and leads you away from illusion.” And also: “Close your eyes, ears and mouth. Listen to the subtle inner nada.”
There is also a well-known and often quoted allegory in the Bhagavata Purana, which is well worth giving here because of its beauty: “Lord Krishna left his place at midnight and went into the jungle. It was a full moon night in the first month of winter. He began to play his flute. The echo of the flute permeated the calm and undisturbed atmosphere. The music was heard by the gopis (cowherd girls). They immediately left their houses and their husbands and forgot all their duties and past life. They ran straight to the place where the nada of the flute was being played. They started to dance around the flute player. After some time each of the gopis discovered that she was dancing with Krishna.”
This story is symbolic and illustrates the path of nada yoga. The nada from the flute is heard at midnight, which is the best time to practise nada yoga. Krishna is higher consciousness. The sound of the flute is the nada that arises from the underlying consciousness. The gopis represent the aspirant and the senses, both of which are normally overwhelmed and distracted by day to day worldly life. But when the inner nada (sound of the flute) is heard then the awareness is directed inwards towards Krishna (pure consciousness). Eventually the gopis merge with Krishna they tune in with pure consciousness. This is the path of nada yoga.