The moon shines by the reflected light of the sun.
When the sun has set, the moon is useful for revealing objects.
When the sun has risen, no one needs the moon,
though the pale disc of the moon is visible in the sky.
So is it with the mind and the Heart.
The mind is useful because of its reflected light.
It is used for seeing objects.
When it is turned inwards,
The source of illumination shines forth by itself,
and the mind remains dim and useless
like the moon in day-time.
- Ramana Maharshi (from Heart Is Thy Name, O Lord)