"Take people as a mirror, you can know the gains and losses" means taking people as a mirror, you can know your own gains and losses. This sentence comes from the old Tang book Biography of Wei Zhi.
Original text:
Biography of Wei Zhi in Old Tang Dynasty
Author: Shao Liu
Dynasty: Jin
Sighed: "with copper as a mirror, you can dress your clothes;" Taking history as a mirror, we can know the rise and fall, and taking people as a mirror, we can know the gains and losses. I have tried to protect these three lessons, and I defend myself from the heart. Today, Wei Zhi died, and so will he. "
Translation:
Emperor Taizong sighed: "using copper as a mirror can make you dignified and tidy when wearing it;" Taking history as a mirror, we can know the rise and fall of existence since the dynasties; Take people as a mirror, you can know your own gains and losses. I used to keep these three mirrors to prevent myself from making mistakes. Now that Wei Zhi is dead, I have lost a mirror. "
Extended data:
Taking people as a mirror, we can know the gains and losses. Compared with people's passivity, we emphasize the initiative of Emperor Taizong and my subjective initiative. Taking copper as a mirror and dressing appropriately means that people look in the mirror, not me; Taking history as a mirror and knowing the rise and fall is to learn history, not to take the initiative to find people with historical knowledge.
In the same way, the same logic, learning from others and understanding gains and losses means that people take the initiative to "learn from others" and actively understand gains and losses. The first two points are about initiative and consciousness, and "learning from others" certainly emphasizes initiative and consciousness.
Generally speaking, Emperor Taizong emphasized more introspection, more understanding, more self-denial, more introspection by Confucius, more introspection by Si Qi, more introspection by Ceng Zi, more introspection by seek fortune for oneself by Mencius and more introspection by Zhu Xi.