《明史·列传·卷六十七》
 以陛下的聪明盖世，岂有不知道对宦官不能够委任信用，然而难免误用，大概是没有讲习端正本心的学问。
以陛下聪明冠世，岂不知刑臣不可委信，然而不免误用者，殆正心之学未讲也。
With Your Majesty's supreme cleverness, how can you not know that eunuchs cannot be entrusted with credit? However, it's hard to avoid misuse, probably because there's no study on the learning of correcting the original intention.