《礼记·檀弓上》
子思的母亲在父亲死后改嫁到卫国，现在死了，子思前去奔丧。卫国有个叫柳若的对子思说： 您是圣人的后代，各地的人都在关注您如何为嫁母持丧，您可得当心一点。 
子思之母死于卫，柳若谓子思曰： 子，圣人之后也，四方于子乎观礼，子盖慎诸。 
Zisi's mother remarried to Wei after his father died, and she had just died, so Zisi went to mourn. A man from Wei named Liu Ruo said to Zisi: “You are a descendant of the sage, and people from all over are paying close attention to how you will mourn your remarried mother, so you must be careful.”