The Complete Works of Wei Yuan is ***20 volumes, "Light is seen in the court and shines on the world."
When a courtyard is exposed to the sun, you can see a place the size of a house. When the world is exposed to the sun, it can illuminate every corner in all directions.
Meaning: The more information you receive, the more comprehensive your understanding of things and the broader your horizons. In other words, it is: listen clearly, listen dark.
reference data
Complete works of Wei Yuan and Wei Yuan. Hongkong: China Culture, 2006.