In the Tang Dynasty , there was an eminent monk named Zen Master Guling. When he was young, he became a monk in Fuzhou and practiced with the local eminent monks. Later, Zen Master Gu Ling left Fuzhou and went to Baizhang Mountain in Hongzhou, where he worshiped under the disciples of the eminent monk Baizhang Master.

After Zen Master Gu Ling studied under Zen Master Baizhang for a period of time, his cultivation indeed improved by leaps and bounds, and he finally attained enlightenment. After enlightenment, Zen Master Gu Ling decided to return to Fuzhou.
The reason why Gu Ling decided to go back to Fuzhou actually had an unexplained reason in his heart, that is, he wanted to save his early master.
In the mind of Zen Master Gu Ling, the early master in Fuzhou was indeed a very knowledgeable person. In the words of our modern people, he can be regarded as a high-level intellectual. But it's a pity that the master has too much stubbornness of a scholar and doesn't know how to adapt at all.
In terms of meditation practice, if you only know how to read scriptures and cannot study quietly with your mind clear, you will obviously not be able to achieve enlightenment. Therefore, after enlightenment, Zen Master Gu Ling decided to go back, hoping that he could help his master achieve enlightenment as soon as possible.

Unfortunately, although the master was very pleased with the achievements of Zen Master Gu Ling who had returned from school, he did not take his advice for a long time. Although he was very polite to Gu Ling in words and even showed a hint of respect, in terms of actions he did not follow his persuasion and still maintained the practice of studying scriptures.
Zen Master Gu Ling also knows that the master has thought that he has been studying Buddhism all his life, but he has no idea about the true enlightenment and practice of Zen. He only knows how to read and practice sutras, and he only talks about the principles when lecturing others, which is far from enough for his own inner efforts.
But after all, the other party was his former master. Once a master, he was always a father. Gu Ling couldn't be too straightforward, so he had to temporarily put aside the idea of advising and wait for the time to come.

On this day, the master was sitting in front of the window reading scriptures again, with Zen Master Gu Ling quietly accompanying him. He happened to see a fly smacking against the window, apparently trying to get out of the window to the yard outside.
But the window had just been newly covered with window paper, and no matter how hard the fly tried, it couldn't get through. It could only keep hitting it for a long time, but it was still useless.
Seeing this scene, Zen Master Gu Ling had a flash of inspiration in his mind and said loudly:
The world is so vast, but you are unwilling to go there, so you only know how to dig into old paper. What's the use of this? Aren’t we just stuck on the surface of the broken paper and unable to reach the vast world?

Zen Master Gu Ling actually made a pun. On the surface, he was referring to the fly. It was strange that it kept crawling in and out of the window paper, but how could it get out?
But in fact, it is a reminder to Master that if you don’t know how to realize your original mind and just read the scriptures, hoping to find the Dharma in the words, you will definitely not be able to find it.
It is said that after hearing this sentence, the master of Zen Master Gu Ling immediately became enlightened and became enlightened. Later he also became enlightened and achieved great achievements.
Later, before his death, Zen Master Gu Ling said a Buddhist verse:

There are thousands of rivers and moons in front of the door, but there is no dust in the room. If the bay leaves can cover your eyes like a picture, you must know that the pure land is also charming.
The meaning of this Buddhist verse is that inner peace and outer brightness are what practitioners should yearn for and pursue.
If your sight is blocked by the Bayeux Sutra and you think that reading the Sutra can lead to practice and become a Buddha, you are totally wrong. Because Zen Buddhism is not based on words, and it does not seek Buddhism, Dharma, or Sangha. Trying to use scriptures to pursue the state of Zen will obviously not lead to enlightenment.
The Bay-leaf Sutra looks dazzling, but if you are confused by it, then the Buddha statues in the temple will also bewilder you. The more you insist on tranquility and Bodhi, the more you will be bound by the tranquility and Bodhi.

In fact, life is like this. Wisdom should not be covered by dust, and the heart should be dust-free, just like there is a quiet bright moon.