John Wesley on Revelation 16:2

And the first went - So the second, third, &c., without adding angel, to denote the utmost swiftness; of which this also is a token, that there is no period of time mentioned in the pouring out of each phial. They have a great resemblance to the plagues of Egypt, which the Hebrews generally suppose to have been a month distant from each other. Perhaps so may the phials; but they are all yet to come. And poured out his phial upon the earth - Literally taken. And there came a grievous ulcer - As in Egypt, Exod 9:10,11. On the men who had the mark of the wild beast - All of them, and them only. All those plagues seem to be described in proper, not figurative, words.