Albert Barnes Commentary Psalms 102:20

"To hear the sighing of the prisoner; To loose those that are appointed to death;" — Psalms 102:20 (ASV)

To hear the groaning of the prisoner - Meaning here, probably, the captives in Babylon; those who were held as prisoners there, and who were subjected to such hardships in their long captivity. See the notes at Psalms 79:11.

To loose those that are appointed to death - Margin, as in Hebrew, “the children of death.” Compare the notes at Matthew 1:1. This may mean either those who were sentenced to death; those who were sick and ready to die; or those who, in their captivity, were in such a state of privation and suffering that death appeared inevitable.

The word rendered “loose” means, properly, to “open,” applied to the mouth for eating, Ezekiel 3:2; or in song, Psalms 78:2; or for speaking, Job 3:1; or to the ear, Isaiah 50:5; or to the hand, Deuteronomy 15:8; or to the gates of a city, a door, etc., Deuteronomy 20:11. Then it means to set free, as by opening the doors of a prison, Isaiah 14:17; Job 12:14. Here it means to “set free,” to deliver. Compare Isaiah 61:1.