朝令夕改

Origin and story

Chao Cuo's memorial on valuing grain, preserved in the Book of Han's economic treatise, describes farming families pressed by labor, bad weather, and unpredictable levies. He says orders issued in the morning are altered by evening. Families with grain must sell cheaply to meet demands; others borrow at ruinous rates or sell property, while merchants profit from their urgency.

The wording there is 朝令而暮改. Later uses substitute 夕 for 暮 and condense the sentence. The idiom criticizes unstable directions that make it hard for people to plan or comply. It does not mean that correcting a genuinely mistaken decision is always wrong.