Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 1
It is the usual fit and the same round of thoughts mechanically repeated that you always get in these fits. These thoughts have no light in them and no truth, for the physical mind which engenders this routine wheel of suggestions is shut up in surface appearances and knows nothing of deeper truth or the things of 
the spirit. There is plenty of “increment”, but with this superficial part of the physical mind it is not likely or possible that you can see it. Your impression of the dwindling light is also an impression of this mind natural to it especially in its periods of darkness; for that matter when the periods of darkness come to any sadhak they always seem darker than before; that is the nature of the darkness, to give that impression always. It is also quite according to the rule of these reactions that it should have come immediately after a considerable progress in bhakti and the will to surrender in the inner being – for it comes from the spirit of darkness which attacks the sadhak whenever it can, and that spirit resents fiercely all progress made and hates the very idea of progress and its whole policy is to convince him by its attacks and suggestions that he has made none or that what progress he has made is after all null and inconclusive.
The laws of this world as it is are the laws of the Ignorance and the Divine in the world maintains them so long as there is the Ignorance – if He did not, the universe would crumble to pieces, utsīdeyur ime lokāḥ, as the Gita puts it. There are also, very naturally, conditions for getting out of the Ignorance into the Light. One of them is that the mind of the sadhak should cooperate with the Truth and that his will should cooperate with the Divine Power which, however slow its action may seem to the vital or to the physical mind, is uplifting the nature towards the Light. When that cooperation is complete, then the progress can be rapid enough; but the sadhak should not grudge the time and labour needed to make that cooperation fully possible to the blindness and weakness of human nature and effective.
All the call for faith, sincerity, surrender is only an invitation to make that cooperation more easily possible. If the physical mind ceases to judge all things including those that it does not know or are beyond it, like the deeper things of the spirit, then it becomes easier for it to receive the Light and know by illumination and experience the things that it does not yet know. If the mental and vital will place themselves in the Divine Hand without reservation, then it is easier for the Power to work and produce “tangible” effects. If there is resistance, then it is natural that it should take more time and the work should be done from within or as it might appear underground so as to prepare the nature and undermine the resistance. It seems to me that the demand for patience is not so terribly unreasonable.