The Buddhist Blog:
Hui-k'o, who would be the Second Patriarch of Ch'an, stood in the snow outside the cave. To show Bodhidharma his sincerity to learn the Dharma, Hui-k'o cut off his arm and said, "Your disciple's mind has no peace as yet. Master, please, put it to rest."
Bodhidharma said, "Bring me your mind, and I will put it to rest." Hui-k'o said, "I have searched for my mind, but I cannot find it." Bodhidharma said, "I have completely put it to rest for you."
~Peace to all beings~