《资治通鉴·唐纪·唐纪七十四》
我已经委派张护卫成都城，对于违令杜法的人，他若是抓来告诉我，我还可以赦免；如果他先行斩杀了然后才告诉我，我也不能救助了！ 
吾已委张勍护之矣，彼幸执而白我，我犹得赦之；若先斩而后白，吾亦不能救也！ 
I have appointed Zhang to guard the city of Chengdu. For those who violate the order and commit crimes, if he arrests them and tells me, I can still forgive them; if he kills them first and then tells me, I can't save them!