Su Tung-po, a scholar of the Imperial Academy, once debated with Ch'an Master Chao-chueh about the Path to enlightenment. During the debate, they touched upon the question of whether both sentient and non-sentient beings could attain perfect wisdom. Inspired by the discussion, Su wrote three poems to express what he had learned. Their titles were "Before Practicing Ch'an," "While Practicing Ch'an," and "After Becoming Enlightened through the Practice of Ch'an."
The first poem read as follows:
The second poem expressed a different state of mind, while Su engaged in Ch'an practice:
The final poem described Su's feelings after he had attained realization through Ch'an practice:
After this experience, Su Tung-po thought even more highly of his own understanding of the Dharma. When he was told that Ch'an Master Ch'eng-hao from Yu-ch'uan Temple in Chingnan was so incisive that his timely questions defied response, Su Tung-po refused to believe it. He went to visit the Master in civilian clothing to test the latter's knowledge of Ch'an. As soon as he met the Master, he asked, "I was told that you're very good at Ch'an meditation. May I ask, what is meditation?"
The Master did not answer Su Tung-po's question, but instead asked, "Sir, may I have your name, please?"
Su Tung-po replied, "My name is Scale, which weighs all the abbots who are on Earth."
Upon hearing this, the Master gave a loud shout and asked, "May I ask how much that shout weighs?"
Su Tung-po had nothing to say in reply, but simply stood up, prostrated, and left.
(Source: Hsing Yun's Ch'an Talk, Book 4)