And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image. A noisome and grievous sore - This is a reference to the sixth Egyptian plague, boils and blains, Exodus 9:8, Exodus 9:9, etc.
Related Commentaries of Revelation 16:2
Revelation 16:2
2 And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image.