If the foundation is firm the building can withstand calamities. The practice of yoga is the foundation so that the self is not shaken under any circumstances.
Why should you practice Yoga? To kindle the divine fire within yourself. Everyone has a dormant spark of divinity in him which has to be fanned into flame.
Look after the root of the tree, and the fragrant flower and luscious fruits will grow by themselves. Look after the health of the body, and the fragrance of the mind and richness of the spirit will follow.
Is it necessary to practice all these asanas, further and further? Is it necessary to develop scientific researches further and further? To a yogi, the body is a laboratory, a field of experiments and perpetual researches.
