卧薪尝胆这个成语源于中国春秋时期的一段历史故事，讲述了越王勾践在遭受吴国战败后，忍辱负重、发愤图强的故事。这个成语不仅体现了个人的坚韧不拔，也象征着一个国家或民族在逆境中奋起的精神。

原文：

吴既赦越，越王勾践反国，乃苦身焦思，置胆于坐，坐卧即仰胆，饮食亦尝胆也。曰：“汝忘会稽之耻邪？”身自耕作，夫人自织，食不加肉，衣不重采，折节下贤人，厚遇宾客，振贫吊死，与百姓同其劳。欲使范蠡治国理民，因与共谋。

越王勾践复国后，每日以苦行激励自己，将苦胆放置于座位旁，无论坐卧还是饮食时都会品尝，以此提醒自己不要忘记被俘的耻辱。他亲自参与农耕，夫人亲自纺织，生活极为简朴，甚至比普通百姓还要清苦。同时，他还虚心向贤士请教，厚待宾客，救济贫困者，并且关心逝者的家属。在这样的努力之下，越国逐渐恢复了元气。

译文：

After Wu forgave Yue, King Goujian of Yue returned to his country and subjected himself to hard work and deep thought. He placed a gallbladder in his seat and tasted it whenever he sat or lay down, as well as during meals. He would ask himself: "Have you forgotten the humiliation at Kuaiji?" He personally engaged in farming while his wife took up weaving. Their diet was simple without any meat, and their clothing plain without rich colors. He humbled himself before learned men and treated guests generously. He also helped the poor and consoled the bereaved, sharing the hardships with the common people. He appointed Fan Li to govern the state and discussed strategies with him.

通过这段原文和译文，我们可以看到勾践复国之路的艰辛与不易。他用自己的实际行动诠释了什么是真正的坚韧不拔。这也正是“卧薪尝胆”这一成语所要传达的核心精神——在困境中保持清醒的头脑，不断自我鞭策，最终实现目标。

总结来说，“卧薪尝胆”不仅仅是一个人的奋斗史，更是中华民族自强不息精神的体现。它告诉我们，在面对困难和挑战时，只有勇于承担、积极进取，才能迎来胜利的曙光。