1. Source: "The Analects of Confucius·Yan Yuan": "A gentleman is respectful and courteous to others. Within the four seas, we are all brothers."

2. Within the four seas, we are all brothers. All are brothers, Sihaifan refers to the world, that is, the whole country, which means that people in the world love each other like brothers and live in harmony. People from all over the world are like brothers. Often used to describe people willing to help you wherever you go.