God is the friend of silence. See how nature -- trees, flowers, grass -- grow in silence; see the stars, the moon, the sun, how they move in silence... The more we receive in silent prayer, the more we can give in our active life. We need silence to be able to touch souls. The essential thing is not what we say, but what God says to us and through us. All our words will be useless unless they come from within.
The person who sits is more ready to bring forth clear things than someone who walks or stands. Sitting means peace. Thus we sit, which is bowing in humility among all creatures. Then the individual comes to a quiet peace reaching this peace in light. The light is given in the silence wherein one sits and dwells.