Here we have a repetition of the "Ninth Egyptian Plague," that of DARKNESS. Ex. 10:21-23. This is the "day" spoken of by Joel. "A day of darkness and of gloominess, a day of clouds and of thick darkness." Joel 2:1-2. Christ speaks of it in Mark 13:24, as the time when "the Sun shall be darkened, and the Moon shall not give her light."
Notice that this Plague immediately follows the Plague of "Scorching Heat," as if God in mercy would hide the Sun whose rays had been so hard to bear. The effect of the darkness was to make men gnaw their tongues for PAIN and for their SORES, showing that these Plagues overlapped each other, or followed in such rapid order that they were not over the sufferings of one before they were suffering from another, and that they were limited to a short period of a few months, and not distributed over a period of years as the Historical School of interpretation claims.
The notable feature is, that their sufferings brought no repentance, but caused them to blaspheme the God of Heaven. Some talk of conversion in Hell, and of the ultimate restoration of the wicked, but it is not revealed here. If Hell's torments will cause men to repent, why do not the torments of those under these plagues lead to repentance? No, it only causes them to blaspheme the more, and while sin and impenitence last, Hell lasts. This Plague extends over the whole Kingdom of the Beast.