Once Yunmen said, "There is nothing whatsoever that does not explain the Dharma. Striking the bell or beating the drum is no exception. If this is the case, nothing will be Dharma, and nothing will not be."
  He added, "One should not assert that when one speaks, it is, and that when one doesn't speak, it isn't. Even what I just said has not quite made it. Well, as long as it benefits people, it may be okay. . . ."

from Zen Master Yunmen, Urs App, trans