Union of mind and body is yoga
An important point which has been omitted by the commentators is that hath yoga is not only the union of prana and mind. In fact , it means the union of prana and mind with self. So , in hath yoga , ida nadi represents the negative force , the flow of consciousness, pingala represents the positive force , the flow of vital energy , and sushumna nadi represents the neutral force , the flow of spiritual energy.