sì hǎi zhī nèi jiē xiōnɡ dì 四海之内皆兄弟
All the People Within the Four Seas Are Brothers.
This saying means that all the people in the world are as close as brothers. The Four Seas are the East, West, South, and North seas. The ancient Chinese believed that heaven was round and the earth was square, with China in the middle of the earth, which was surrounded on all four sides by the Four Seas.”Within the Four Seas” refers to the world inhabited by humans, which was also called “all under heaven,” referring to the whole country or the whole world. This saying shows the inclusive and broad mind of the Chinese and their compassion, love and friendship towards other human beings.
Zixia said, “So long as a man of virtue always does things conscientiously without making mistakes and treats people respectfully and appropriately, then all the people within the Four Seas will be his brothers. Why should he then worry about having no brothers?” (The Analects)