Silence in the work of a mystic is not necessarily stillness. Silence to a mystic is self control.
In the conception of a mystic silence does not mean only the closing of the lips or the closing of the eyes; silence for a mystic is suspension of every activity, which he gains by different degrees, by controlling the movement, by controlling the words, by controlling the breath and by controlling the thoughts. The mystic attains mastery over himself, which he considers the only mastery worth having, by the practice of silence.
Silence does not mean a few hours meditation, sitting quiet, talking to no one, but it means the work of control continued throughout one's daily life from morning till evening. If not, a few moments silence everyday do not suffice the purpose.
If one was to count how many useless words one speaks throughout the day, words which are unnecessary, and thus spends energy and vigour, the center of which the breath, in this way wasting his breath by speaking the words that are of no use either to himself or to the other. Many times a man talks because he thinks it is good to be pleasant, and being pleasant means speaking uselessly. If there is nothing to speak about, then he wishes to grumble against the weather.
Many disagreements are caused by excessive talking and many misunderstandings can be avoided if only a person had the control over his words.
(Hazrat Inayat Khan, at the Netherlands, January 1923)