战国时代，有一个叫冯谖的人，在齐国孟尝君门下作食客。
有一次，冯谖替孟尝君到薛地去讨债。
他假装孟尝君下的命令，叫这些人不用还钱。
薛地人民都以为这是孟尝君的恩泽，对孟尝君十分感激。
冯谖等于帮孟尝君买了“义”回来。
所以，后来孟尝君被齐王解除官职，回到薛地居住，受到人民热烈的欢迎。
这时冯谖对孟尝君说：“聪明的兔子都有三个洞藏身，才能免于猎人杀害的危险。但是你现在只有一个洞，还不能把枕头垫得高高的，无忧无虑地睡觉。我会再帮你另外找两个安全的洞。”
于是，冯谖去见梁国的国君梁惠王。
他告诉梁惠王，孟尝君非常的能干。
如果能请他帮忙治理国家，那梁国一定能富国强兵。
于是，梁惠王连续三次派人邀请孟尝君当梁国的宰相。
冯谖都叫孟尝君不要答应。
这个消息传到了齐国，齐王非常的紧张，连忙也派人请孟尝君回来齐国当相国。
同时，冯谖要孟尝君向齐王请求，在薛地兴建宗庙，以确保薛地的安全。
等到宗庙建好后，冯谖对孟尝君说：“现在三个洞都已经挖好了，从此以后，你就可以把枕头垫得高高的，无忧无虑地睡觉了！”
后来，“高枕无忧”这句成语就从这里演变而出。
它用来形容做事有周详准备，感觉很安心，无忧无虑。
During the Warring States period, there was a man named Feng Xuan who served as a guest in the house of Mengchang Jun, a nobleman in the state of Qi.
Once, Feng Xuan went to collect debts for Mengchang Jun in Xue.
He pretended that it was Mengchang Jun's order and told the people that they didn't need to repay the money.
The people of Xue thought this was Mengchang Jun's kindness and were very grateful to him.
Feng Xuan helped Mengchang Jun buy 'righteousness' with this act.
So later, when Mengchang Jun was removed from his official position by the king of Qi and returned to live in Xue, he was warmly welcomed by the people.
At this time, Feng Xuan said to Mengchang Jun, "Smart rabbits have three holes to hide in to avoid being killed by hunters. But now you only have one hole, and you can't rest your head on a high pillow and sleep soundly without worry. I will help you find two more safe holes."
So Feng Xuan went to see King Hui of Liang.
He told King Hui that Mengchang Jun was very capable.
If he could ask him to help govern the country, Liang would surely become wealthy and powerful.
King Hui then sent envoys three times to invite Mengchang Jun to be the prime minister of Liang.
Feng Xuan advised Mengchang Jun not to accept each time.
When this news reached Qi, the king of Qi became very anxious and immediately sent an envoy to invite Mengchang Jun back to Qi to be the prime minister.
At the same time, Feng Xuan asked Mengchang Jun to request permission from the king of Qi to build an ancestral temple in Xue to ensure its safety.
After the temple was built, Feng Xuan said to Mengchang Jun, "Now all three holes have been dug. From now on, you can rest your head on a high pillow and sleep soundly without worry!"
Later, the idiom 'sleeping soundly' evolved from this story.
It is used to describe feeling at ease and free from worry because of careful preparation.
