Chinese idiom · 成语
温故知新
Meaning
Review the old to know the new; learning through reflection.
Character by character
Origin and story
philosophical sayingThe Wei Zheng chapter of the Analects (論語) records Confucius saying that a person who revisits what is already known and gains fresh understanding from it can serve as a teacher. The familiar four-character idiom compresses the longer sentence, which contains an extra 而 between 'review the old' and 'know the new.'
This is a statement about learning, rather than a story of a particular student receiving a lesson. Its two halves belong together: keeping old knowledge available matters, but so does discovering something further in it. The image of warming something again suggests returning to material actively. Mere repetition without any renewed understanding captures only part of the saying's force.
Sources and further reading
In everyday life
重读去年的读书笔记，我对这本书有了新的理解，真是温故知新。
Rereading last year's notes gave me a new understanding of the book—a real case of gaining fresh insight from old learning.
For discovering new understanding through reviewing earlier learning, not simply memorizing again.