Why do some people say that it is better to guard against a gentleman than a villain? How to explain this sentence?

The sentence "Better guard against gentlemen than villains" means that it is better to guard against gentlemen with moral cultivation than against villains with ulterior motives.

This sentence comes from a sentence in the Book of Changes: "courtesy guards against gentlemen and law guards against villains." It means "courtesy is used to control gentlemen, and law is used to prevent villains." This leads to the saying that "it is better to prevent a gentleman than a villain".

This statement is not biased against the gentleman, but because the gentleman has evil thoughts in his heart, and only because of moral constraints will he abide by the rules. And villains often do whatever it takes to achieve their goals. Therefore, the cost of preventing villains will be higher, and it is often impossible to prevent.

To sum up, the phrase "it is better to guard against a gentleman than a villain" reminds people to pay attention to their own moral cultivation, take self-discipline, honesty and morality as the criteria, and at the same time guard against villains who may cause harm to themselves.