懲前毖後

Simplified: 惩前毖后

chéngqiánbìhòu ㄔㄥˊ ㄑㄧㄢˊ ㄅㄧˋ ㄏㄡˋ

    • lit. to punish those before to prevent those after (idiom) to criticize former mistakes firmly to prevent them happening again

Character by character

Sources