huǐ悔zhī之wú无jí及
To regret something when it is already too late to change or rectify it; to regret in vain.
Era:
Ancient
Frequency:
Story:
During the Spring and Autumn period, King Fuchai of the State of Wu was preparing to attack the State of Qi. King Goujian of the State of Yue brought his people to show support for Fuchai. Wu Zixu, an advisor to King Fuchai, warned him that the State of Yue was the true menace and should be eliminated. He cautioned that if Yue was allowed to grow stronger, it would be too late for regrets when they eventually sought revenge.
Fuchai, however, disregarded Wu Zixu's advice, alienated him, and eventually ordered him to commit suicide.
Eleven years later, the now powerful State of Yue launched a decisive attack and completely destroyed the State of Wu.