What is the meaning of [The fairest rose is at last withered]

Beauty fades and is gone. Here is a verse from _The Ruba’iyat of Omar Khayyam_
, translated by Edward FitzGerald:

> Oh, come with old Khayyam, and leave the Wise
> To talk; one thing is certain, the Life flies;
> One thing is certain, and the Rest is Lies;
> The Flower that once has blown for ever dies.