Albert Barnes Commentary Job 3:18

"There the prisoners are at ease together; They hear not the voice of the taskmaster." — Job 3:18 (ASV)

There the prisoners rest together - Herder translates this, “There the prisoners rejoice in their freedom.” The Septuagint, strangely enough, “There they of old (ὁ αἰώνιοι hoi aiōnioi) assembled together (ὁμοθυμαδόν homothumadon) have not heard the voice of the exactor.” The Hebrew word שָׁאַן shâ’an means “to rest, to be quiet, to be tranquil”; and the sense is that they are in the grave, freed from chains and oppressions.

They hear not the voice of the oppressor - Of him who exacted taxes, who laid on them heavy burdens, and who imprisoned them for imaginary crimes. He who is bound in chains, and who has no other prospect of release, can look for it in the grave and will find it there. Similar sentiments are found respecting death in Seneca, ad Marcian, 20: “Mors omnibus finis, multis remedium, quibusdam votum; haec servitutem invito domino remittit; haec captivorum catenas levat; haec a carcere reducit, quos exire imperium imponens vetuerat; haec exulibus, in patriam semper animum oculosque tendentibus, ostendit, nihil interesse inter quos quisque jaceat; haec, ubi res communes fortuna male divisit, et aequo jure genitos alium alii donavit, exaequat omnia; haec est, quae nihil quidquam alieno fecit arbitrio; haec est, ea qua nemo humilitatem suam sensit; haec est, quae nulli paruit.” The sense in Job is that all are at liberty in death.

Chains no longer bind; prisons no longer incarcerate; the voice of oppression no longer alarms.