Peter Brook's 1989 interpretation of Krishna revealing the Bhagavad Gita to Prince Arjuna (excerpt from the Mahabharata).
There's more to the story:
and the final words of Bhishma
In India it is said that if it does not appear in the great epic of the Mahabharata it does not exist. As Krishna says, "the true battlefield has no weapons." It's an inside job.