Which ancient poem does Shushan come from?

There is a diligent road in Shushan, which comes from Han Yu's Persuading Ancient and Modern Scholars in the Tang Dynasty.

The content is "Shushan has a hard road, and learning the sea is endless." Tell people that there is no shortcut on the road of reading and learning, and there is no boat sailing smoothly. In the vast sea of books and mountains of learning, "diligence" and "concentration" are both indispensable, and they are also the best conditions for learning more and more knowledge.

Han Yu was born in Heyang, Henan (now mengzhou city, Henan). Self-proclaimed "King of Changli County", known as "Han Changli" and "Mr. Changli" in the world. An outstanding writer, thinker, philosopher and politician in the Tang Dynasty. Han Yu was an advocate of the ancient prose movement in the Tang Dynasty, and was honored by later generations as the first of the "eight masters in the Tang and Song Dynasties". He and Liu Zongyuan are also called "Liu Han", and they are known as "great writers" and "one hundred generations of literators". Later generations, together with Liu Zongyuan, Ouyang Xiu and Su Shi, are also called "the four great writers of the ages". His prose writing theories, such as "the unity of literature and Taoism", "moderation in speech", "doing good deeds" and "having a proper speech", have important guiding significance for future generations. He is the author of The Collection of Han Changli.