Friends:
Essentially Luminous, but veiled by defilement is Mind:
The exalted
Buddha once said:
Friends, I know of no other single thing, so quickly changing as this
swift mind,
insofar as it is not easy to find just one other phenomena changing equally
fast.
Shining bright, friends, is this mind, yet it is obstructed by
external defilements.
Luminous absolutely, is that pure mind, when it is
safely
released and freed from
these alien impurities. Naturally Radiant is this mind, though
it is soiled by these
accumulated foreign obscurations. This, the ordinary unlearned persons cannot
understand as it really is! I tell you, that is why uneducated ordinary
persons
neither meditate nor develop mentally. Luminous is that mind,
friends,
when it is
purified & released from these fermented pollutions. This does
the
learned Noble
Disciple fully understand as it really is. I tell you, that is why
that
educated Noble
Disciple develops & improve mentally by training meditation...

Source: The Numerical Discourses of
the Buddha: Ańguttara Nikāya
I 8-11:
http://What-Buddha-Said.net/Canon/Sutta/AN/AN.I.8-10.htm
More on the Magnificent
Luminous Mind:
http://What-Buddha-Said.net/drops/II/In_Control.htm
http://What-Buddha-Said.net/drops/II/Non-Control.htm
http://What-Buddha-Said.net/drops/IV/Mind_Reading.htm
http://What-Buddha-Said.net/drops/II/Blazing_&_Bright.htm
http://What-Buddha-Said.net/drops/II/The_Core_Duality.htm
http://What-Buddha-Said.net/drops/II/Magnificent_Mind.htm
http://What-Buddha-Said.net/drops/II/Highway_to_Nibbana.htm
http://What-Buddha-Said.net/drops/III/Focusing_on_Mentality.htm
http://What-Buddha-Said.net/drops/IV/Omniscient_Quantum_Mind.htm
http://What-Buddha-Said.net/drops/IV/Immersing_the_Body_in_the_Mind.htm

Updated:
22 November 2009 http://What-Buddha-Said.net/drops/Luminous_is_Mind.htm