快马加鞭

Origin and story

Wang Anshi's poem sending Chunfu to Jiangnan ends with an affectionate request: remember how much you will be missed, and on returning, urge on even a fast horse. The preceding lines recall youthful companionship and contrast the travelers' changing stages of life. Speed here serves the wish for an early reunion, not a military emergency.

The poem contains the longer wording 快馬亦須鞭. The exact four-character phrase appears in the Ming play Sha Gou Ji, in a call to hurry to someone's rescue. The modern idiom retains the idea of increasing an already active pace, especially when a task or journey needs to be finished sooner.