《孔子家语·子路初见》
孔子说： 国君如果没有敢谏的臣子就会失去正道，读书人没有敢指正问题的朋友就听不到善意的批评。
孔子曰： 夫人君而无谏臣则失正，士而无教友则失听。
The Master said, "A prince who can not find a counsellor to tell him of his errors will lose his realm, and a scholar who can not find a friend to tell him of his errors will not have his learning completed."