Medical science also now recognises that if you are in perfect vital equilibrium, you do not catch illness or in any case you have a kind of immunity from contagion. If you have this equilibrium, this inner harmony which keeps the envelope intact, it protects you from everything. There are people who lead quite an ordinary life, who know how to sleep as one should, eat as one should, and their nervous envelope is so intact that they pass through all dangers as though unconcerned. It is a capacity one can cultivate in oneself. If one becomes aware of the weak spot in one’s envelope, a few minutes’ concentration, a call to the force, an inner peace is sufficient for it to be all right, get cured, and for the untoward thing to vanish.
Ref: Questions and Answers 1950 – 1951