《魏书·列传·卷三十六》
知人固然很不容易，但人也不易知道自己，我既然失之在内心，崔浩也外显漏于形体。
知人固不易，人亦不易知。吾既失之于心内，崔亦漏之于形外。
It is not easy to understand others, it is also not easy for a person to understand himself, as I have failed internally, while Cui Hao failed externally.