Zengzi said: “I heard this from the Master: If a man ever reveals his true nature, it’s when he mourns his parents.”
Zengzi said: “I heard this from the Master: The one facet of Meng Zhuangzi’s filial piety that others couldn’t match was that he retained his father’s officials and continued his father’s policies.”
Zengzi is reiterating Confucius’s comments in Chapter XI of Book 1 and Chapter XX of Book 4 of the Analects that the true test of a son’s filial piety is whether he observes the three-year mourning period after the death of his parents:
Confucius said: “When the father is alive, observe his son’s intentions. When the father is dead, watch his son’s conduct. If after three years he has not deviated from his father’s path, then he may be called a dutiful son.”
Confucius said: “If for three years after his death the son does not alter his father’s ways, he is a good son indeed.”
As I’ve argued before, this was more than likely honored more in breech than practice.
Meng Zhuangzi was the head of the second most powerful warlord clan in Confucius’s home state Lu. The most powerful clan was the Ji family.