Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 3
The obstacle or wall of bondage which you feel is simply that of the habits of the ordinary physical consciousness. It is so with all,– the ordinary vital nature with its ego, desire, passions, disturbances, and the ordinary physical nature with its strong habits and outwardness are the chief obstacles that have to be overcome in the nature. When they fall quiet, then it is easier to enter into the true consciousness and unite with the Mother. But they are not accustomed to quietness and as soon as it is felt they want to come out of it and resume their ordinary movements. But this will go when the inner has sufficiently gained on the outer to dominate it. The inner things will grow and come out 
more and more as you feel the inner faith growing until they are strong enough to rule the outer conduct. The obstacles you feel, the surging up of old things and repetition of restlessness etc. are due to this strength of habit of the physical nature – it lives by repeating always the same things and the same movements to which it has been accustomed in the past. The inner influence as it comes out will more and more create for it new habits of thought and feeling and action and it will then dwell firmly in these and not in the things of the old nature.