A Zen master who wanted to choose a successor out of his disciples said to them, "Any of you who thinks himself capable of becoming my successor should write four lines in front of my door to show his teaching" A disciple who was a great scholar, wrote on the master's door, "The mind is like a mirror. Dust gathers on it. Clean the dust and you know what is"
Hui-neng another disciple of the master who was cleaning rice for twelve years in the kitchen, laughed at the lines of the scholar. He was taken to task by the other disciples who glorified the scholar's lines. They challenged him to write something better. Hui-neng who had unlearned to write in the last twelve years, requested the help of someone to write his lines as he dictated. He said " The mind is not a mirror at all. Where can the dust gather? One who knows it, knows it"
The master on reading the lines of Hui-neng took him aside and confirmed his enlightenment and chose him as his successor by handing over his robe to him. However he asked him to abscond from the place as the scholars could harm him. Hui-neng thus fled from the place with the robe and hid himself in the forest. He was tracked by the scholar. Hui-neng came forward to hand over the robe saying that he was happy cleaning rice and by getting the robe he had to run away and hide himself.
He then dropped the coat down for the scholar to pick it up. However the scholar could not pick it up as the robe seemed to be heavy. He then confessed to Hui-neng that the robe itself was unwilling to go with him. He requested him to teach him the truth as what he knew were mere words. Hui-neng pointed out to him, that the whole problem lay in his learning too much and that he had to unlearn to go beyond the understanding of the mind and the intellect. An understanding not of the mind but of the total being would then dawn which would present the truth.