The term “once more” unambiguously connects this cry to the “loud voice” of Revelation 19:1. The “voice” of Revelation 19:1 is singular, yet now John uses the plural pronoun “they.” That can be understood by recalling that the single “voice” of Revelation 19:1 was composed of “a great multitude,” that is, innumerable voices in unison. Hence the plural “they” in Revelation 19:3.
3 Once more they cried out, “Hallelujah! The smoke from her goes up forever and ever.”