Chapter 15 introduces “the seven angels having the seven last plagues.” This is a reiteration of the sending forth of the wrath of God as witnessed by the several series of signs earlier in the book. Note the text says that with the pouring out of the plagues of the seven angels, “the wrath of God is complete.” This is the exact same comment made in chapter 10:7 prior to the sounding of the seventh trumpet.
What does the word COMPLETE mean in English; and what does a corresponding word mean in any language on the face of the earth, since the beginning of time until now?
While we have seen the revelation of the mystery of God completed by the opening of the seventh seal, likewise we now are told the wrath of God finds its completion in the sending forth of the seven plagues held by the seven angels. We are again looking at signs identifying parallel events.
Re-introduction of the theme of the victorious saints is found verses 2 – 5 give the immediately familiar picture of the victorious saints singing praise to the Lamb in, “the song of Moses the servant of God, and in the song of the Lamb.” We were introduced to the cry of the martyrs and the 144,000 first in Chapter 7, and again in Chapter 14; and following that we have the theme of the victorious saints, whom God will now avenge having set in motion his requiting process.