【明報專訊】We use this expression to remind people who criticise (批評) others that they should be careful because they may have the same faults (缺點、錯誤). This comes from the fact that all cooking pans become black with soot (煤煙) when cooked over an open fire. None is any different than the other. "Carl's comments about Martha being a bad driver is a case of the pot calling the kettle black. Do you know how awfully he drives?"