According to a hymn in Shvetashvataropanishad, when the traits of Yoga enters into the body which is composed of five elements – earth, water, fire, air and space, one does not receive disease, aging or death who receives the fire of Yoga(II.12).
Our body is a miniature universe. Spiritually universe is composed of five elements – earth, water, fire, air and space and so our body is composed of. Through the practice of yogic exercises(tapa) we give heat or fire to the body. Every exercise supplies heat to the body. But in Yoga, not only heat but mind is applied to each and every part of the body. For this the heat of Yoga is so much vital to the body.
The characteristic of heat or fire is to purify a substance by burning undesirable and foreign matter contaminating the substance. Similarly the fire of Yoga burns undesirable and foreign matter entering into the body which is composed of five basic elements. When these elements are purified, the body is purified and when body is purified one easily dispels disease, aging and death.
Yoga is not only an exercise of body but also an exercise of mind. In fact mind is more important than the body. The greatest thing in the universe is our mind. Body is the direct and complete manifestation of mind. A single body is the manifestation of a single mind and this universe is the manifestation of all minds of all beings inhabiting the universe.
Mind and soul(atman) are the same. If soul is an ocean of consciousness, mind is its waves. This soul as well as mind pervades every part and every cell of the body. Every cell is conscious and lively because of this soul and mind. For this, mind has a great influence over the body. We can dispel disease, aging and death through the will power of mind.
Disease, old age and death are the same thing. Disease accelerates the coming of old age and old age generates fear of death in the mind. When mind is in the grip of fear of death, one succumbs to death early.
Soul is indestructible, eternal, immortal and ageless. It is the source of unending life and consciousness. In every birth this soul fills up our body with unending life and consciousness. Soul is always pure and never contaminated. Since the body is inhabited by such a soul, which pervades and rules over every cell, the body should remain pure, uncontaminated and ageless always. Disease or old age cannot be a part of this body. If disease or old age affects the body, it is because of our ignorance.
Body has a natural immune system to protect it from disease. Common cold, cough, fever, loose motion etc. are not the symptoms of disease but the symptoms of the body fighting against the invading foreign matter into the body. These symptoms show that body is flushing out germs and impurities from the body. Because of ignorance or over sincerity we fear of some disease and rush to a doctor. With doctor’s prescribed drugs we get immediate relief but by this the immune system is not strengthened. So as a result we suffer from recurrent illness. The wild animals and nomadic people seldom fall ill because they do not see disease as disease.
Similarly we can feel freshness and youngness in old age through the practice of true Yoga and following true spiritualism. When we choose traditional and religious belief and practices we fail to rejuvenate us from old age. An old man gets trapped in the traditional belief that one who has born must die. He sees that people seldom live after 70 or 80 years of age. This is true, but a Yogi should not think about disease, aging or death. Death is dead and it is lifeless. So how can a lifeless thing take away life? death is like darkness. As darkness disappears through a burning candle, so the darkness of death disappears on acquiring true knowledge about true self.
From the time immemorial the greatest challenge before men is to win over death and the endeavour of spiritual people has been to win over it. When one wins over death one wins over birth also cuts off the cycle of birth and death. This is called liberation or salvation. When one wins over death, it does not mean that one cannot die. One takes birth and leaves this world at his will. To live for ever is again a bondage.
Salvation should come when one is alive. Several hymns of the Upanishads teaches men to get liberated from birth and death while one is alive. But religious leaders would teach people to work in the service of God so that after death they may be liberated and may enter into heaven. A true Yogi should not wait for liberation after death. Liberation after death is a misleading sermon given by those who are far away from true spiritualism and Yoga. Their aim is to make people religious so that they may rule over them. True freedom and true liberation lies in the self.