And they had tails like unto scorpions - The fancy of an Arab now often discerns a resemblance between the tail of the locust and the scorpion. See the remark of Niebuhr, quoted in the notes on Revelation 9:7.
And there were stings in their tails - Like the stings of scorpions. See the notes on Revelation 9:3. This made the locusts which appeared to John the more remarkable, for though the fancy may imagine a resemblance between the tail of a locust and a scorpion, yet the locusts have properly no sting. The only thing which they have resembling a sting is a hard bony subsubstance like a needle, with which the female punctures the bark and wood of trees in order to deposit her eggs. It has, however, no adaptation, like a sting, for conveying poison into a wound. These, however, appeared to be armed with stings properly so called.
And their power was to hurt men - Not primarily to kill people, but to inflict on them various kinds of tortures. See the notes on Revelation 9:5. The word used here - ἀδικῆσαι adikēsai, rendered “to hurt” - is different from the word in Revelation 9:5 - βασανισθῶσιν basanisthōsin, rendered “should be tormented.” This word properly means “to do wrong, to do unjustly, to injure, to hurt”; and the two words would seem to convey the idea that they would produce distress by doing wrong to others, or by deeding unjustly with them. It does not appear that the wrong would be by inflicting bodily torments, but would be characterized by that injustice toward others which produces distress and anguish.
Five months - See the notes on Revelation 9:5; (also Editor’s Preface).