Answer: The first explanation: Beard and hair can't be destroyed by others. "The Book of Filial Piety" emphasizes: "Parents dare not damage the body and skin. Filial piety begins. " In ancient times, protecting beard and hair was considered as the most basic filial piety. Besides, there is a further relationship between men and beards. The ancients didn't want to grow a beard, but they wanted to stay. There is a saying that "mother doesn't celebrate her birthday, but father doesn't have a beard".
Second, there is a sequence of beards. If the father dies, the beard on the upper lip can grow long. If the mother dies, the chin beard can grow long. If parents die, they will be together. After the beard is left, it can only be simply trimmed, but not completely shaved. Beard is to express grief and miss parents, so beard has a great relationship with parents. So what I want to convey is that I can devote my life to my country, but I don't allow my beard to get dirty, in order to make my parents filial.
Third, if you shave and cut your hair. If someone in the family dies, once a man knows the bad news, he can't have a haircut or shave for a month or a hundred days. Among them, belief may be because the body is subject to parents, so it is not abandoned when the ancestors die, to show filial piety to their parents and express their grief and thoughts; Some people also say that it is to recall the sadness of the old friend and arrange the face to show filial piety; Others say that not cutting hair or shaving is to change their appearance, so that the dead can't identify clearly, so as not to hurt themselves.
In a word, the respect for the dead is eternal, regardless of ancient or modern times. This is not superstition, but also the inheritance of etiquette. From the point of view of medical health, it is also not allowed to touch the dead. We should look at the natural laws of birth, aging, illness and death objectively, let the dead rest in peace and let the living go on as usual.