Two and a half thousand years ago, Lord Buddha said that the greatest thing in the world is to give health, but the greatest of all great things is to give spiritual health. Today I think this saying has to be reversed, and to give physical and mental health is the greatest service to the world, because without these, spiritual health cannot come. There is a very good definition in the Kathopanishad that the body is a chariot, the organs of action and perception are the horses, the intelligence is the rein and the one who holds the intelligence is the rider. If there is a disturbance in the chariot, then the charioteer cannot control the horses. If the charioteer is skilful, but his chariot is not good, then his skill has no value at all. And it is said that the chariot, which is the body, and the horses, which are the senses, are controlled by the intelligence, the rein. Then the dweller in the body and the dwelling place, the body, both can realise the soul, which is as small as the head of a pin and as vast as the universe.
B.K.S. Iyengar, London, 1984