There is a light that shines beyond all things on earth, beyond us all, beyond the heavens, beyond the highest, the very highest heavens. This is the light that shines in our hearts.
~ Chandogya
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.