Job 21:13 – They spend their days in prosperity. In an instant they go down to Sheol. — World English
Job is speaking here of the wicked. Although they “grow in power” (Job 21:7) and “their houses are safe from fear, neither is the rod of God upon them”, they, like all of us, eventually die and go to sheol. (Ecclesiastes 9:2,3,5,10; Romans 5:15-19; 1 Corinthians 15:21,22) Any thought of these wicked ones going to a section of sheol to be tortured has to be read into what Job said.
They spend their days in prosperity…
In speaking of their works as prosperous, Job is not saying that their prosperity is due their striving to live a life according to righteous principles, but in success according the standards of the present crooked generation, loving the things of this world more than they love God. These people often enjoy almost perfect health, which may, in effect, be a curse for them, for they, not suffering much along the manner of sickness, and knowing little pain, lack the empathy for the suffering of others, and often their manner of life leads them to condemn those who are suffering as simply receiving what is due to them.
In an instant they go down to Sheol.
Job tells how many of these, living a life of luxury, do not die a death of suffering, but they seem to simply cease to live instantly, and go into the Bible hell, sheol, the realm of death. But as some have stated, death is common equalizer of all, the one who seeks to do good and the wicked, the poor and the wealthy, the wise and the fool. “There is one event to the righteous and to the wicked; to the good, to the clean, to the unclean, to him who sacrifices, and to him who doesn’t sacrifice. As is the good, so is the sinner; he who takes an oath, as he who fears an oath.” — Ecclesiastes 9:2, World English.