on the throne of the beast
Like the first bowl, the fifth bowl specifically targets those within the kingdom of the Beast. Unlike the first bowl which affects all men who took his mark, this bowl is designated for the throne of the Beast, and his kingdom becomes full of darkness. This may imply a focus upon the leadership of his kingdomthe Beast himself and those in the higher echelons of his realm. Or it could mean all those under his mark. His throne was obtained from Satan. See commentary on Revelation 13:2. He is both a ruler, the little horn (Dan. Dan. 7:8) and Eighth Head (Rev. Rev. 17:11+), and a kingdom, the Terrible Beast (Dan. Dan. 7:7; Rev. Rev. 13:2+). See Beasts, Heads, and Horns. If the literal Babylon is to be rebuilt, it may already have become the place of the throne of Satan by the time that is in view here under the fifth bowl.1 Rev. 13:18+); therefore his throne is in a definite place: rebuilt Babylon on the Euphrates, we believe,Satans ancient capital, in the land of Shinar, where wickedness is to be set on its base in the end-time (Zec. Zec. 5:5-10).2
his kingdom became full of darkness
Now the kingdom of the Beast is struck with a plague reminiscent of that which struck Pharaoh at the hand of Moses:
Then the LORD said to Moses, Stretch out your hand toward heaven, that there may be darkness over the land of Egypt, darkness which may even be felt. So Moses stretched out his hand toward heaven, and there was thick darkness in all the land of Egypt three days. They did not see one another; nor did anyone rise from his place for three days. But all the children of Israel had light in their dwellings. (Ex. Ex. 10:21-23)The transition from the fourth to the fifth bowls is most striking. The one had been the fiery, scorching, blinding brightness of the sun; the next is an impenetrable darkness.3 Although the throne of the Beast is empowered by Lucifer,4 the shining one, the son of the dawn (הֵילֵל בֶּן־שַׁחַר [hêlēl ben–šaḥar] , Isa. Isa. 14:12), he is helpless to illumine the God-imposed darkness. See The Plagues of Egypt and the Tribulation.
they gnawed their tongues because of the pain
Pain is πόνου [ponou] which includes affliction, anguish.5 The darkness with which they are afflicted is more than just lack of light as in the Egyptian plague, but also seems to involve other means of affliction which result in intense pain, perhaps similar to that experienced at the hand of the demonic locusts, although that judgment was broader than upon the Beasts throne and kingdom (Rev. Rev. 9:5-6+). They meditate revenge and are unable to effect it; hence their frenzy [Grotius]. Those in anguish, mental and bodily, bite their lips and tongues.6 The people who suffer these plagues bit their tongues, chew them, gnaw them, as their best diversion from their misery. Their tongues have spoken blasphemies, and they themselves thus punish them.7
4 From lux, light, and fero, to bear, bring, carry.
6 A. R. Fausset, The Revelation of St. John the Divine, in Robert Jamieson, A. R. Fausset, and David Brown, A Commentary, Critical and Explanatory, on the Old and New Testaments (Oak Harbor, WA: Logos Research Systems, Inc., 1997, 1877), Rev. 16:10.
7 J. A. Seiss, The Apocalypse: Lectures on the Book of Revelation (Grand Rapids, MI: Zondervan Publishing House, 1966), 374.