Gong Jing asked Yan Zi: What is clean and long-term politics? Yan Zi replied: Just like water. Beautiful clear water. If it is turbid, it will pollute the road. If it is clean, it will wash away the pollution, so it will last for a long time.

Gong Jing said: Clean politics will soon perish. What is it like? Yan Zi replied: It is as hard as a stone. This big stone looks hard and feels strong. It's hard inside and outside, and it won't last long, so it will soon perish.