《后汉书·列传·逸民列传》
听说黄、老之言，乘虚入冥，藏身远遁，也有治国养民，在政治方面有所作为。
盖闻黄、老之言，乘虚入冥，藏身远遁，亦有理国养人，施于为政。
It is said that Huang and Lao's words are used to ride the emptiness into the underworld, hide and escape, and also have something to do in politics to govern the country and support the people.