Jamieson, Fausset and Brown on Job 20:26

26. All darkness--that is, every calamity that befalls the wicked shall be hid (in store for him) in His (God's) secret places, or treasures (Jude 13; De 32:34).

not blown--not kindled by man's hands, but by God's (Is 30:33; the Septuagint in the Alexandrian Manuscript reads "unquenchable fire," Mt 3:12). Tact is shown by the friends in not expressly mentioning, but alluding under color of general cases, to Job's calamities; here (Job 1:16) Umbreit explains it, wickedness, is a "self-igniting fire"; in it lie the principles of destruction.

ill ... tabernacle--Every trace of the sinner must be obliterated (Job 18:15).