Albert Barnes Commentary Revelation 9:10

"And they have tails like unto scorpions, and stings; and in their tails is their power to hurt men five months." — Revelation 9:10 (ASV)

And they had tails like unto scorpions. The imagination 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 imagination may imagine a resemblance between the tail of a locust and a scorpion, yet locusts properly have no sting. The only thing they have that resembles a sting is a hard bony substance, 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 locusts, however, appeared to be armed with stings properly so called.

And their power was to hurt men. Not primarily to kill men, but to inflict on them various kinds of tortures. See the notes on Revelation 9:5.

The word used here—adikhsai, rendered to hurt—is different from the word in Revelation 9:5—basanisywsi, rendered should be tormented. This word specifically 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 dealing unjustly with them. It does not appear that the wrong would be by inflicting bodily torments, but would be characterized by that injustice towards others which produces distress and anguish.

Five months. See the notes on Revelation 9:5.