Revelation 9:4

And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree, but only those men which have not the seal of God in their foreheads.

Here is a picture which presents extraordinary convulsions in nature in order to teach the coming of great upheavals in the Church: And the fifth angel sounded his trumpet; and I saw a star fallen out of heaven to the earth, and to him was given the key of the pit of the abyss. John saw this star, not in the course of falling, but as having fallen, as ready to begin his fearful work of destruction. He was given the key to a fearsome cavity, to the pit of the abyss, the abode of the devil and his angels; he received the power to bring men into this abode of darkness and damnation.

John now relates that the fallen angel made use of his power: And he opened the pit of the abyss, and smoke arose out of the pit like the smoke of a great furnace; and the sun was darkened, and the air, from the smoke of the pit. The pernicious activity of the wicked fallen star is here shown, by which dark and poisonous vapors from the abyss of hell were unloosed. It was not a small and temporary phenomenon, but one which brought forth such a dense cloud of hellish smoke as to obscure the sun himself and to render the entire air murky. This evil was afterward made still worse: And out of the smoke there came forth locusts upon the earth, and to them was granted power as the power which the scorpions of the earth wield; and it was told them that they must not injure the grass of the earth nor any green thing nor any tree, but only those men that do not bear the seal of God upon their foreheads. So the dense and poisonous vapor resolved itself into a swarm of infernal spirits in the form of locusts, which were rendered more dangerous by the additional power of stinging like scorpions. The enemies of the believers, of the Church of Christ, are often compared to locusts, both on account of their great number and because of their destructiveness, Jeremiah 46:23; Amos 7:1; Joel 1:1. However, their power was not unlimited, since they were expressly told that they must not injure the vegetation which the Lord had still permitted to stand, and since they were not allowed to harm the elect of the Lord, who bear the seal of the heavenly Father and of the Lamb on their foreheads, Revelation 7:3.