Just as a goldsmith purifies gold, so must the body be constantly purified and purged so that the inner gold may shine.
Iyengar yoga is a complete, powerful and precise system of physical, mental and spiritual culturing.
Its aim is the union of the individual spirit with the universal spirit.
Its method of achieving this lofty aim is mainly through the perfection of yoga postures (asanas) and yogic breathing (pranayama). Concentration on perfecting the alignment in asanas engrosses the mind in progressively subtler aspects of one's self which begins with the body, but ends with the very Self within.
When the beginner attempts the asanas, the mind struggles to find even the gross parts of the body like the arms and legs and how to control and move them as required. Progressively the mind is made to respond to and control subtler parts of the body as well as coordinate these parts. This process expands the depth and breadth of the mind improving its ability to focus on and penetrate an object as well as expanding its capacity from single pointed concentration to multi pointed concentration. By stages, the mind moves from concentration to awareness. In responding to and controlling the many parts of the body, the mind is controlled since it can not go away from the body. In this state, the mind becomes merged and suffused in its object. As the object is controlled, so too is the mind. The sense of a separate self fades and the mind becomes stilled like the water of a reflecting pond. In it, the true Self within is glimpsed. That glimpse lends perspective to our life and satisfies our deepest urges for understanding.
To the casual observer the postures may look merely physical, but practiced with fervor, sensitivity and devotion they become a road to profound understanding of one's Self.