New Defender's Study Bible Notes
16:2 had the mark. This judgment will not be on just the third part of men this time (compare Revelation 9:15), but upon all the men destined for hell (Revelation 14:9-11). They had preferred the mark of the beast to suffering for Christ; now they will suffer anyhow. The selective application of this grievous sore may have some connection with the nature of the “mark” (perhaps activated through chemical or electronic means) which they will have received on their skins; whatever substance the angel pours out on the earth will perhaps react with the mark and infect it with incurable pain.