Zeng Guofan once said to his son: "Choosing friends is the first priority in life." Later, he said it in a more straightforward and concise sentence: "Choosing friends is choosing people, and choosing people is the first priority."

Zeng Guofan's friends were all hardworking and motivated people. Zeng Guofan often warned his friends and relatives to stay away from those who were not enterprising and doing nothing. Zeng Guofan's younger brother wanted to go to Hengyang to study, but Zeng Guofan strongly opposed it because many people there were mediocre and did not want to make progress. Zeng Guofan was afraid that his younger brother would be influenced by these people and develop a habit of being lazy and gluttonous over time. Therefore, Zeng Guofan strongly recommended his younger brother to go to Changsha to complete his studies. With the help of good teachers and friends such as Luo Zenan and Li Xubin, his two younger brothers eventually became great men.

Zeng Guofan's behavior towards his brother also confirms the old saying: "He who keeps company with the good becomes good, and he who keeps company with the bad becomes bad." This means that people will influence each other. If you keep company with lazy and decadent people, you will eventually become tired of studying and lose your ideals. However, if you keep company with those who are eager to learn and hardworking, you can encourage each other and make progress together. Zeng Guofan once summarized the principle of "eight friendships and nine non-friends" for making friends, warning others to stay away from mediocre, lazy, and mean people, and make more good friends. This principle is not only a principle for making friends, but also a rule for knowing people.