The word "flesh" refers to humanity. The prophet Isaiah compares humanity to grass that grows and dies quickly. AT: "All people will die like grass dies, and all their" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-simile]])
Here the word "glory" refers to beauty or goodness. Isaiah compares the things that people consider to be good or beautiful about humanity to flowers that die quickly. AT: "goodness soon stops, just as flowers soon die" (See: [[rc://en/ta/man/translate/figs-simile]])