Understanding the essence of the Six Classics involves hundreds of works. Even if you can't improve your moral conduct and simple social customs, you can learn a skill and help yourself. You can't rely on your father's eldest brother for a long time, and your hometown can't always be safe from war. One day, if you drift away, there will be no one to protect you, so you have to turn to yourself. The proverb says, "No matter how much money you accumulate, it is better to learn a skill.". "The easiest thing to learn and admire in skills is reading. People in the world, whether ignorant or wise, want to know a lot of people and know a wide range of things, but if they refuse to read and study, it's like eating enough but being too lazy to cook, dressing warmly but being too lazy to make clothes. People who like to read books know how many people under the universe, see how many things under the universe, and see the success or failure and likes and dislikes of human beings. Needless to say, even things in heaven and earth and things in ghosts and gods can be well understood.