A.T. Robertson Commentary Revelation 14:11

"and the smoke of their torment goeth up for ever and ever; and they have no rest day and night, they that worship the beast and his image, and whoso receiveth the mark of his name." — Revelation 14:11 (ASV)

The smoke of their torment (ο καπνος του βασανισμου αυτων). See 9:5 for βασανισμος, only there it was a limited penalty, here it is "for ever and ever" (εις αιωνας αιωνων, unto ages of ages). See also 18:9; 19:3; 20:10.

They have no rest (ουκ εχουσιν αναπαυσιν). The very language used in 4:8 of the four living creatures in praising God. "Those who desert Christ for Caesar will be the victims of a remorse that never dies or sleeps" (Swete). The rest of the verse repeats the solemn challenge of verse 9.