Our physical bodies age and lose their strength. Despite all our anti-aging creams and pills and rejuvenating treatments of every kind, slowly the wrinkles creep across our face and our hair turns grey. Regardless of what we do to care for our bodies, eventually they grow old, and we can do nothing to stop that process. In the case of consciousness, there are certain states of mind that have become familiar to us over the years and that continue even as we grow old or live with illness. If we have always been cheerful and calm, for example, we will continue to be cheerful and calm even in our old age. So the qualities of the body will eventually disappear no matter how much we might do to try and safeguard them, but the qualities of the mind, if we have really trained and cultivated familiarity with them, will remain for as long as the mind itself continues. That is why we can say that the qualities of the mind can be developed infinitely and boundlessly.
— His Holiness The Dalai Lama , Mind in Comfort and Ease