Zeng Zi was one of Confucius' students. Once, Zeng Zi's wife was going shopping. Because the child was crying loudly, she promised the child that she would kill their pig to treat him after she returned home.

After she returned, Zeng Zi captured¹ to butcher the pig. His wife stopped him, saying "I was kidding the child." Zeng zi said: "There is no kidding with the children, because they know little and they usually imitate their parents and follow their instructions. If you cheat them, it is the same as teaching² them to cheat the others." So Zeng Zi killed the pig.

He knew that sincerity³ and keeping one's words are the essentials of conducting oneself. If he broke his words, he might keep his pig, but he would leave a unforgettable shadow in his child's heart.

曾子是孔子的学生，有一次，曾子的妻子准备去赶集。由于孩子哭闹不已，曾子妻许诺孩子回来后杀猪给他吃。

曾子妻从集市上回来后，曾子便捉猪来杀，妻子阻止说：“我不过是跟小孩子闹着玩的。”曾子说：“和孩子是不可说着玩的，小孩子不懂事，凡事跟着父母学，听父母的教导。现在你哄骗他，就是教孩子骗人啊。”于是曾子把猪杀了。

曾子深深懂得，诚实守信，说话算话是做人的基本准则。若失言不杀猪，那么家中的猪保住了，但却在一个纯洁孩子的心灵上留下不可磨灭的阴影。