《韩非子·内储说下六微》
郑君说： 太子已经确立了，您却说没有出生，为什么？ 郑昭回答说： 太子虽然确立了，但是君王的好色之心不减；宠爱的姬妄如果有了儿子，君主必定喜爱他；喜爱他，就一定想把他立为继承人，所以我说太子还没有出生。 说六
君曰： 太子已置，而曰 未生 ，何也？ 对曰： 太子虽置，然而君之好色不已，所爱有子，君必爱之，爱之则必欲以为后，臣故曰 太子未生 也。 △说六
The monarch of Zheng said: The crown prince has already been established, but you say he has not yet been born, why? Zheng Zhao replied: Although the crown prince has been established, the king's lustful heart has not diminished; if the favored Lady Wang has a son, the monarch will definitely love him; if he loves him, he will definitely want to make him the heir, so I said that the crown prince has not yet been born.