One day, a monk asked Venerable Zen Master Un-Mun,
“When I don't give rise to any thought, is there an error or not?”
Master Un-Mun said,
“Sumeru!” (Error is as big as Mount Sumeru.)

Zen Master Seong Do said, “If thought should arise, there could be either sin or error.
But if no thought should arise, there could not be any error.
Nevertheless, why did Master Un-Mun say that even when the student did not raise a single thought,
error was as big as Mount Sumeru?

Now, any of you, give me a word!”