No one understood the flower sermon,
except the one who smiled. The flower sermon communicated the ineffable nature of such-ness-
which is the transmission of wisdom without words.
There is the form of the formless, the subtle eternal truth that does not rest on words or letters but is a special transmission of presence.
This cannot be found in any book, mantra or prayer. This is why the one who knows does not speak and the one who speaks does not know.
Then what can anyone do but point at the moon and be misunderstood?
Hold up a flower and wait.
I have not learned anything else.