Mend the fold after a sheep is lost
During the Warring States Period (475-221 BC)， the State of Chu not very powerful. The king and the important court officials were dissolute and incompetent. They indulged in luxury and excessive pleasure all the time. Zhuang Xin, one of the ministers foresaw that the country was in danger. One day he remonstrated with the king: "Your Majesty, wherever you go, you're always surrounded by people who flatter you with what you like. They try everything to make you happy so that you forgot to tend to state affairs. If you go on like this, no doubt, the country will perish sooner or later."
The King of Chu flew into a rage. "How dare you! You even use such vicious words to curse my country and mean to arouse resentment among the people!" Zhuang Xin explained, "I dare not curse the State of Chu. But I really have a premonition that Chu is facing GREat danger." Seeing that the king is especially fond of those corrupt officials and trust them in everything, the minister thought Chu is bound to extinct. So he asked the king to let him leave Chu. He wanted to go to the State of Zhao and stay there for a while.
The king gave him the leave.
Five months later, the King of Qin sent his troops to invade Chu and occupied a large tract of its territory. The King of Chu himself went into exile. Now, the king remembered Zhuang Xin's words. He sent his men to fetch him. When the king saw Zhuang Xin again, he asked him, "What can I do now?"
Zhuang Xin replied, "It's not too late if you mend the sheepfold when you find a sheep is missing." He then made some good suggestions to rehabilitate the state and recover the lost land. The king was very much pleased.
The idiom "Mend the fold after a sheep is lost" has developed from Zhuang Xin's answer to the king.
We still use this metaphor to advise someone that even when he has made a mistake and suffered losses, he can still remedy it by drawing lessons from the mistake.
亡羊补牢
战国时期，楚襄王统治楚国时，国势不振。楚王和重要的大臣都荒淫无能。他们一直沉溺于奢侈享乐之中。大臣庄辛预见到楚国会发生危险。一天他劝谏楚王说：" 陛下，无论你走到哪儿，身旁总是那些奉承你的人，他们想尽办法让您高兴，您就忘了处理国事。长此以往，国家迟早会灭亡的。"
楚王大怒："大胆！你居然用这样恶毒的话来诅咒我的国家，蓄意挑起人民的不满！" 庄辛解释说："我不敢诅咒楚国，但我可以预言楚国正面临着巨大的危险。" 庄辛见楚王如此宠信那些腐败的大臣，相信楚国必定要亡国。于是他向楚王请求离开楚国，到赵国居住一段时候。
楚王同意了，他便到赵国去了。五个月之后，秦君果然派军入侵楚国，占领了大片土地。楚王被迫流亡。这时，他想起了庄辛的劝谏，于是派人接庄辛回来。楚王见了庄辛，便问："现在我该怎么办呢？"
庄辛回答说："丢了羊，就把羊圈修好，不算迟。然后他提出许多如何重振国家，收复失地的好谋略。楚王非常高兴。
成语"亡羊补牢"就是由庄辛对楚王的回答而来的。比喻事情出了差错，有了损失，如果及时补救，还能够弥补，吸取教训。
