Tree Graffiti, Berlin, 2010
One of my favorite Buddhist quips is the one in the title. I like it because it reverses the argument from authority that you quite often find in religious discourse, also including Buddhism.
The quip is actually an assertion of the form
If P, then Q.However, the specific P and Q in it actually make it a reversal of another assertion, which is a bit like
If Bubba said it, then it's true.