A monk asked Chao-chou Ts’ung shen (777-897) (Joshu), “Has the oak tree Buddha nature?”
Chao-chou said, “Yes, it has.”
The monk said, “When does the oak tree attain Buddhahood?”
Chao-Chou said, “Wait until the great universe collapses.”
The monk said, “When does the universe collapse?”
Chao-chou said, “Wait until the oak tree attains Buddhahood.
– The Gateless Barrier, The Wu-Men Kuan (Mumonkan),
Translated by Robert Aitken, Case 37