The human time is over and the human life is very long. What does it mean?

Grave Bed - Gu Cheng

I know that eternal death is coming, and I am not sad

My wishes are placed in the pine forest

Below There is a sea, which looks like a pool from a distance

What follows me little by little is the afternoon sunshine

The human time is over and the life is very long

I should rest in the middle

People who pass by say that the branches are low

People who pass by say that the branches are growing

Gu Cheng's "Tomb Bed" expresses his pessimism about life nothingness. A few decades of life are very short, but the human world is very long and will exist as long as the earth still exists. A person's life is between the long life and the short life, and he should rest (die).