Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 1
It is in the silence of the mind that the strongest and freest action 
can come, e.g. the writing of a book, poetry, inspired speech etc. When the mind is active it interferes with the inspiration, puts in its own small ideas which get mixed up with the inspiration or starts something from a lower level or simply stops the inspiration altogether by bubbling up with all sorts of mere mental suggestions. So also intuitions or action etc. can come more easily when the ordinary inferior movement of the mind is not there. It is also in the silence of the mind that it is easiest for knowledge to come from within or above, from the psychic or from the higher consciousness.