“Prior to everything, asana is spoken of as the first part of Hatha Yoga. Having done asana, one attains steadiness of body and mind, freedom from disease and lightness of the limbs.”
Hatha Yoga Pradipika (1:17)
Asanas means a state of being in which one can remain physically and mentally steady, calm, quiet and comfortable. In Raja Yoga, asana refers to the sitting position, but in Hatha Yoga it means something more. Asanas are specific body positions which open the energy channels and psychic centers. They are tools to higher awareness and provide the stable foundation for our exploration of the body, breath, mind and beyond. The hatha yogis also found that by developing control of the body through asana, the mind is also controlled. Therefore, the practice of asana is foremost in Hatha Yoga.
Sw. Satyananda Saraswati (APMB)