From Paulo Coelho's blog.
A violent samurai warrior with a reputation for provoking fights for no reason arrived at the gates of a Zen monastery and asked to speak to the master.
Without hesitating, Ryokan went to meet him.
"They say that intelligence is more powerful than brute force," said the samurai. "Can you explain to me what heaven and hell are?"
Ryokan said nothing.
"You see?" bellowed the samurai. "I could explain quite easily: to show someone what hell is, you just have to punch them. To show them what heaven is, you just have threaten them with terrible violence and then let them go."
"I don’t talk to stupid people like you," said the Zen master.
The blood rushed to the samurai’s head. His brain became thick with hatred.
"That is hell," said Ryokan, smiling. "Allowing yourself to be upset by silly remarks."
Taken aback by the monk’s courage, the samurai warrior softened.
"And that is heaven," said Ryokan, inviting him in. "Not reacting to foolish provocations."