Shoyoroku - Case 23: Roso Faces the Wall

Whenever Roso saw a monk coming, he immediately sat facing the wall. Hearing
of this, Nansen said,
  "I usually tell my people to realize what has existed before the kalpa of
   emptiness [1], or to understand what has been before Buddhas appeared in
   the world. Still, I haven't acknowledged one disciple or even a half. If
   he continues that way, he will go on even until the year of the donkey [2]."

[1]: One of the "four kalpas" or periods of cosmic changes: the kalpa of
     creation, the kalpa of existence, the kalpa of destruction, and the kalpa
     of emptiness.
[2]: Since there is no "year of the donkey" in the Chinese zodiac, the
     expression "until the year of donkey" means endlessly.