Hathayoga is a powerful, but difficult and onerous system whose whole principle of action is founded on an intimate connection between the body and the soul. The body is the key, the body the secret both of bondage and of release, of animal weakness and of divine power, of the obscuration of the mind and soul and of their illumination, of subjection to pain and limitation and of self-mastery, of death and of immortality. The body is not to the Hathayogin a mere mass of living matter, but a mystic bridge between the spiritual and the physical being...
In fact the whole aim of the Hathayogin may be summarised from our point of view, though he would not himself put it in that language, as an attempt by fixed scientific processes to give to the soul in the physical body the power, the light, the purity, the freedom, the ascending scales of spiritual experiences which would naturally be open to it, if it dwelt here in the subtle and the developed causal vehicle.
Man, still a child in Nature's mighty hands,
In the succession of the moment lives;
To a changing present is his narrow right;
His memory stares back at a phantom past,
The future flees before him as he moves;
He sees imagined garments, not a face.
Armed with a limited precarious strength,
He saves his fruits of work from adverse chance.