Treat a person you hold a grudge against with upright behavior. “Repaying a grudge with rectitude” was a principle proposed by Confucius（551-479 BC） for dealing with grudges. He felt that both “repaying a grudge with a grudge” and “repaying a grudge with kindness” were incorrect. Confucius argued that one should not deliberately seek vengeance out of momentary anger, nor should one conceal resentment over a grudge and repay it with kindness. Rather, one should analyze the rights and wrongs of the episode which created the grudge, and respond according to the principles of rectitude.

Someone asked, “How about repaying a grudge with kindness?” Confucius said, “Then how would you repay kindness? Repay a grudge with rectitude, and repay kindness with kindness.” (The Analects)