In chapter 50 of the Romance of the Three Kingdoms, the defeated Cao Cao flees by the Huarong road and finds Guan Yu waiting for him. Guan Yu has signed a military pledge to stop him. Cao Cao asks him to “give weight to the feelings of former days.”
Guan Yu answers that he once received Cao Cao’s great kindness, “but I have already repaid it” by killing two enemy generals and lifting a siege. Cao Cao asks whether he still remembers the five passes, where Guan Yu killed Cao Cao’s generals as he left him years before. Guan Yu turns his horse and orders his men to spread out, which plainly means letting Cao Cao go.
Back at camp, Zhuge Liang says: “Guan Yu thought of Cao Cao’s old kindness and let him go on purpose. But there is a military pledge.”