《墨子·20章 节用(上)》
圣王既已去世，听任百姓放纵自己，那些想早点成家的，有时二十岁就成家，那些想迟点成家的，有时四十岁才成家。
圣王既没，于民次也，其欲蚤处家者，有所二十年处家；其欲晚处家者，有所四十年处家。
After the death of the saints, the people were allowed to do whatever they wanted. Those who wanted to get married early would get married at the age of 20, and those who wanted to get married late would get married at the age of 40.