It means: the dead are gone, the living should be strong, live well, and let the dead rest in heaven.
Extended data
"The dead are gone", which means that people can't be resurrected after death, and everything around them goes with him; "The living should be like this" means that the living should inherit and carry forward the will and spirit of the deceased. Although the deceased has passed away, its spirit will last forever.
So the general meaning of these two sentences is: please don't be too sad in the face of the death of the deceased. For the living, it is important to cherish the present, reassure the deceased and live up to the trust and expectation of the deceased.
"The deceased is like a husband, and he doesn't give up day and night" is a famous saying of Confucius, which describes that time keeps passing like running water and never comes back, feeling that things in life are changing rapidly and cherishing time. From Zi Han's The Analects.
Author: Su Shi; "Former Red Cliff Fu": "The deceased is like this, but it has never happened; If the surplus is insufficient, the deficiency will not grow and fail. "
Author: Liu Chenweng "Never mind, the deceased is like this, and it has been a long time."