The 6th Patriarch of Chinese Zen School, Hui Neng, was a man of great wisdom. After receiving teachings from the 5th Patriarch (Hung Jen), he was instructed not to take up ordination immediately as conditions were not ripe for him to propagate the dharma yet. He was told to wait and practice until the conditions ripened.
After practising in seclusion in the rural areas of China for 15 years, he received signs that conditions were ripe for him to take up ordination. He proceeded to Fa Hsin Temple in Canton (Present Day Guangzhou).
When he entered the Temple, a huge crowd had gathered as a high monk was going to give dharma teachings that day. As he was walking in, he found 2 monks disputing about a flag that was fluttering.
1st Monk : “The flag moves”
2nd Monk: “It was the wind that moves”
The 2 of them argued about who was right. Hui Neng found this exchange interesting and remarked
“Dear Sirs! It is not the flag that moves. Neither was it the wind. It is your mind that moves.”
With that, he made his way into the temple and left the 2 monks in awe.