The original sentence is:

As for the ancient sayings, there is no hope of quick success and instant benefit, and there is no temptation of snobbery. Take its roots and realize it, add its cream and hope for its glory. The roots are lush, but the cream is brilliant. A kind and upright person keeps his word.

Vernacular translation:

If you expect to reach the realm of the ancients' statements, don't expect it to come true soon, don't be tempted by snobbery, wait for its fruit like cultivating roots, and wait for its light like refueling a lamp. Roots grow vigorously, fruits are ripe, oil is enough to light up, and benevolent people are amiable.

Creation background

Answer to Li Yi was written in the seventeenth year of Zhenyuan in Tang Dezong (80 1). After being admitted as a scholar in the eighth year of Zhenyuan (792), Han Yu failed to pass the official examination and entered the official career. He is not satisfied with his ambition to use the world, but his ambition to be arrogant with Confucianism, Taoism and "ancient prose" has not diminished. In the 18th year of Zhenyuan (802), he entered Yi Li and studied classical Chinese under Han Yu. This is a letter from Han Yu to Yi Li. At the time of writing this letter, Han Yu was thirty-four years old and was in Chang 'an.