Records of the Three Kingdoms
Cao Hong, courtesy name Zilian, was a younger cousin of Cao Cao. In 190 Xu Rong defeated Cao Cao at Xingyang. Cao Cao lost his horse. Cao Hong gave him the mount and said the realm could do without Cao Hong and could not do without its lord. Cao Cao got away. Cao Hong fought in many campaigns after that and commanded in Guanzhong and toward Hanzhong.
His household was rich and he was stingy. After Cao Pi became emperor he once moved to punish Cao Hong severely because a client had broken the law. Empress Dowager Bian intervened, and Cao Hong kept his life and rank. He died of illness in 232. Giving up the horse is the deed the histories tell first.
Romance of the Three Kingdoms
The novel makes Xingyang closer: Cao Cao’s horse is shot from under him, Cao Hong gives him the mount, goes on foot as escort, and says the realm can do without Hong and cannot do without his lord. Clan loyalty becomes one line on the road of a flight.
Later Cao Hong stays on the Wei lists. The stinginess and the offense to Cao Pi take less space.
Reference: Wikipedia · Cao Hong