《资治通鉴·唐纪·唐纪三十二》
封常清就每天在高仙芝的军府门口等候他出入，数十天都不离开，高仙芝没有办法，只好把他留下。
常清日候仙芝出入，不离其门，凡数十日，仙芝不得已留之。
Feng Changqing was waiting for Gao Xianzhi at the gate of his camp every day for dozens of days. Gao Xianzhi had no choice but to keep him.