《庄子·外篇·至乐》
齐侯必将要求自己而苦苦思索，却仍不能理解，不理解必定就会产生疑惑，一旦产生疑惑便会迁怒对方而杀害他。 况且你不曾听说过吗？
彼将内求于己而不得，不得则惑，人惑则死。且女独不闻邪？
The lord of Qi will probably ask himself over and over again and still not understand. If he does not understand, he will definitely have doubts, and once he has doubts, he will take it out on others and kill him. Furthermore, haven't you heard this before?