During the Warring States period, Mencius traveled to the State of Qi with his disciples. When his advice was not adopted by the King of Qi, he decided to leave. The King offered him 100 jin (a unit of gold), which Mencius politely declined.

However, upon arriving in the State of Song, he accepted 70 jin, and in the State of Xue, he accepted 50 jin.

His student, Chen Zhen, was perplexed by this. He thought, 'These two actions—refusing a large sum and then accepting smaller ones—are contradictory; one of the two must be the correct course of action, and the other wrong.'

Mencius patiently explained the specific circumstances and reasons behind each decision. Chen Zhen then understood and agreed with Mencius's reasoning.