《明史·列传·卷五十三》
卫卒窥伺百官的隐秘之事，有片纸只字上奏立即获罪，公卿大夫没有人不惊恐不安。
卫卒伺百官阴事，以片纸入奏即获罪，公卿大夫莫不惴恐。
The guardsmen spied on the top officials for any wrongdoings, if they submitted a secret report with evidence, the official would be found guilty immediately, and all the high-ranking officials were very frightened and worried.