The quietude and silence which you feel and the sense of happiness in it are indeed the very basis of successful sadhana. <ref>http://incarnateword.in/cwsa/29/peace#p4</ref>
I said once that, to speak usefully for ten minutes, you should remain silent for ten days. I could add that, to act usefully for one day, you should keep quiet for a year! Of course, I am not speaking of the ordinary day-to-day acts that are needed for the common external life, but of those who have or believe that they have something to do for the world. And the silence I speak of is the inner quietude that those alone have who can act without being identified with their action, merged into it and blinded and deafened by the noise and form of their own movement. (The Mother, 26 May 1929) <ref>http://incarnateword.in/cwm/03/26-may-1929#p30</ref>
But even before reaching this point, silence in itself is supremely useful, because in most people who have a somewhat developed and active mind, the mind is never at rest. During the day, its activity is kept under a certain control, but at night, during the sleep of the body, the control of the waking state is almost completely removed and the mind indulges in activities which are sometimes excessive and often incoherent. This creates a great stress which leads to fatigue and the diminution of the intellectual faculties. <ref>http://incarnateword.in/cwm/12/mental-education#p20</ref>
But for the knowledge of the Self it is necessary to have the power of a complete intellectual passivity, the power of dismissing all thought, the power of the mind to think not at all which the Gita in one passage enjoins. This is a hard saying for the occidental mind to which thought is the highest thing and which will be apt to mistake the power of the mind not to think, its complete silence for the incapacity of thought. But this power of silence is a capacity and not an incapacity, a power and not a weakness. It is a profound and pregnant stillness. Only when the mind is thus entirely still, like clear, motionless and level water, in a perfect purity and peace of the whole being and the soul transcends thought, can the Self which exceeds and originates all activities and becomings, the Silence from which all words are born, the Absolute of which all relativities are partial reflections manifest itself in the pure essence of our being. In a complete silence only is the Silence heard; in a pure peace only is its Being revealed. Therefore to us the name of That is the Silence and the Peace. <ref>http://incarnateword.in/cwsa/23/the-purified-understanding#p18 </ref>
Philosophy knows nothing about peace and silence or the inner and outer vital. These things are discovered only by Yoga. <ref>http://incarnateword.in/cwsa/28/the-intellect-and-yoga#p2</ref>
But Yoga is not a mental field, the consciousness which has to be established is not a mental, logical or debating consciousness—it is even laid down by Yoga that unless and until the mind is stilled, including the intellectual or logical mind, and opens itself in quietude or silence to a higher and deeper consciousness, vision and knowledge, sadhana cannot reach its goal. <ref>http://incarnateword.in/cwsa/28/doubt-and-faith#p1</ref>
The silence of the mind does not of itself bring in the supramental consciousness; there are many states or planes or levels of consciousness between the human mind and the Supermind. The silence opens the mind and the rest of the being to greater things, sometimes to the cosmic consciousness, sometimes to the experience of the silent Self, sometimes to the presence or power of the Divine, sometimes to a higher consciousness than that of the human mind; the mind's silence is the most favourable condition for any of these things to happen. In this Yoga it is the most favourable condition (not the only one) for the Divine Power to descend first upon and then into the individual consciousness and there do its work to transform that consciousness, giving it the necessary experiences, altering all its outlook and movements, leading it from stage to stage till it is ready for the last (supramental) change. <ref>http://incarnateword.in/cwsa/29/the-divine-force-in-work#p7 </ref>
Obviously to live in the silent Brahman, the best way is to live within where one can have the silence and resist all outward pulls. <ref>http://incarnateword.in/cwsa/30/the-inward-movement#p57</ref>
In silence lies the source of the highest inspirations. <ref>http://incarnateword.in/cwm/16/letters-to-a-young-sadhak-xii#p8</ref>
=== Silence and Work ===
I said once that, to speak usefully for ten minutes, you should remain silent for ten days. I could add that, to act usefully for one day, you should keep quiet for a year! Of course, I am not speaking of the ordinary day-to-day acts that are needed for the common external life, but of those who have or believe that they have something to do for the world. And the silence I speak of is the inner quietude that those alone have who can act without being identified with their action, merged into it and blinded and deafened by the noise and form of their own movement. (The Mother, 26 May 1929) <ref>http://incarnateword.in/cwm/03/26-may-1929#p30</ref>
I am going to give you two examples to make you understand what true spontaneity is. One—you all know about it undoubtedly—is of the time Sri Aurobindo began writing the Arya, in 1914. It was neither a mental knowledge nor even a mental creation which he transcribed: he silenced his mind and sat at the typewriter, and from above, from the higher planes, all that had to be written came down, all ready, and he had only to move his fingers on the typewriter and it was transcribed. It was in this state of mental silence which allows the knowledge—and even the expression—from above to pass through that he wrote the whole Arya, with its sixty-four printed pages a month. This is why, besides, he could do it, for if it had been a mental work of construction it would have been quite impossible. <ref>http://incarnateword.in/cwm/08/29-august-1956#p4</ref>
The only cure for insomnia is to get rid of the need for sleep by knowing how to obtain mental silence at will. When you can obtain silence at will, you must put your body into a position of absolute repose, stretched out comfortably on the bed; then you go within yourself until there is perfect mental silence and enter a state that is something like a very deep sleep. <ref>http://incarnateword.in/cwm/17/30-may-1966#p3</ref>
But even before reaching this point, silence in itself is supremely useful, because in most people who have a somewhat developed and active mind, the mind is never at rest. During the day, its activity is kept under a certain control, but at night, during the sleep of the body, the control of the waking state is almost completely removed and the mind indulges in activities which are sometimes excessive and often incoherent. This creates a great stress which leads to fatigue and the diminution of the intellectual faculties. <ref>http://incarnateword.in/cwm/12/mental-education#p20</ref>
Generally, when you have what you call dreamless sleep, it is one of two things; either you do not remember what you dreamt or you fell into absolute unconsciousness which is almost death—a taste of death. But there is the possibility of a sleep in which you enter into an absolute silence, immobility and peace in all parts of your being and your consciousness merges into Sachchidananda. You can hardly call it sleep, for it is extremely conscious. In that condition you may remain for a few minutes, but these few minutes give you more rest and refreshment than hours of ordinary sleep. You cannot have it by chance; it requires a long training. (The Mother, 21 April 1929) <ref>http://incarnateword.in/cwm/03/21-april-1929#p11</ref>