“So we would say in yoga that the subtle precedes the gross, or spirit precedes matter. But yoga says we must deal with the outer or most manifest first, i.e. legs, arms, spine, eyes, tongue, touch, in order to develop the sensitivity to move inward. This is why asana opens the whole spectrum of yoga’s possibilities. There can be no realization of existential, divine bliss without the support of the soul’s incarnate vehicle, the food-and-water-fed body, from bone to brain. If we can become aware of its limitations and compulsions, we can transcend them. We all possess some awareness of ethical behavior, but in order to pursue yama and niyama at deeper levels, we must cultivate the mind. We need contentment, tranquility, dispassion, and unselfishness, qualities that have to be earned. It is asana that teaches us the physiology of these virtues.”
―
B.K.S. Iyengar,
Light on Life: The Yoga Journey to Wholeness, Inner Peace, and Ultimate Freedom