RobH_en_tn/job/34/15.md

all flesh

Here all living things are represented by their "flesh." Alternate translation: "all living things" (See: rc://en/ta/man/translate/figs-synecdoche)

mankind would return to dust again

This means that all people would die and their bodies would decay and become soil. In the beginning God created man from the dust. Alternate translation: "the bodies of mankind would soon become soil again" (See: rc://en/ta/man/translate/figs-explicit)