Four mainstream groups within Trinitarian Protestantism are examined regarding their views of the Book of Revelation in the source I quote from below. Of course, there will be more than four ways of understanding Rev. 15:1, but this sample should serve to suffice for a short answer. (Note - all emphases in the quotes are mine.)
Albert Barnes of the 19th century is referred to as one who believes that the Revelation prophecies were/are fulfilled throughout the church age (the Historicist view). The concept of the destruction of anti-Christian forces that have harassed the saints throughout much of the church's history is mentioned, then it says:
"This latter concept is introduced by the appearance of the seven
angels having the seven last plagues, whose role is depicted in
chapter 16. That these are announced to be the 'last plagues' does not
necessarily mean the closing of the affairs of the world, but those
final judgments which will wind up the affairs respecting the beast
and his image." (Revelation, Four Views, Ed. Steve Gregg, p344,
Nelson 1997)
The Preterist view, that the prophecies were fulfilled in the ancient past, e.g. David Chilton circa 1987, takes these seven last plagues to bring about the final end of the once faithful city Jerusalem. The time frame is the end of the Jewish War (A.D. 70). As Chilton writes:
"There is no reason to assume that these must be the "last" plagues in
an ultimate, absolute, and universal sense; rather, in terms of the
specifically limited purpose and scope of the Book of Revelation, they
comprise His great cosmic Judgment against Jerusalem, abolishing the
Old Covenant world-order once and for all." (Ibid. p344)
Merrill C. Tenney, circa 1957, takes the Futurist stance (most prophecies are still to be fulfilled. Verse 1 is said to anticipate verse 7. Apparently they appear in the [literal?] temple, for in verse 6 they step forth out of the temple to execute their mission. Tenney writes:
"The final crisis to which these several parenthetical warning visions
[in ch. 14] point is presented by the climactic judgments of the
bowls..." John "Walvoord [circa 1966] presents one explanation: 'Here
the sea mingled with fire speaks of divine judgment proceeding
from God's holiness'." (Ibid. p345)
The Spiritual view (prophecies fulfilled recurrently throughout history) has three supporters quoted regarding verse 1:
"Many take this to indicate the last judgment acts in history,
i.e., at the end of time. Alford writes:
'There can be no doubt here, not only that the series reaches on to
the time of the end, but that the whole of it is to be placed very
close to the same time. It belongs by its very conditions to the time
of the end.'
"Wilson writes:
'The entire vision (chs. 15, 15) is a great and marvelous portent
because the wrath of God reaches its goal in the end-time
judgements which are symbolized by these last seven plagues.'
"Hendriksen, on the other hand, thinks that the finality of these
plagues is not with reference to history in general, but to individual
sinners who have not repented following the trumpet warnings that God
has sent. Every unrepentant sinner eventually exhausts God's
patience, bringing final judgement upon his life. Hendriksen
writes:
'Throughout the history of the world God's final wrath again and
again reveals itself: now it strikes this one, then another... Thus
conceived, we notice that the vision of the bowls of wrath runs
parallel with all the others and like them covers the entire
dispensation'." (Ibid. pp 345 & 347)
Summary of the Above: Researching this matter, I was struck by the almost total lack of comment about the 'filling up of the wrath of God' to completion, apart from those taking the Spiritual view. Now, it may be that the others DO explain what they understand about this in other literature, but it seems logically impossible for all but the Spiritual view to have no problem with the seven last plagues showing God's wrath being completed - i.e. finished (though even within that camp, some contradict the idea of fully filled-up, completed wrath of God by saying it recurs again and again, only applying to individual sinners.) All who would try to shoe-horn Rev. 15:1 into their overall-interpretation end up having to leave that phrase about God's wrath now being 'filled up' out, because it just won't fit in. The Spiritual view alone seems to largely grasp Rev. 15:1 as the end of a series of plagues from the ascension of Christ - the culmination of many increasing plagues from God, all of which show his wrath against the ungodly, but which now reach a crescendo of deafening proportions - yet still the unspiritual stuff their fingers in their (spiritual) ears and refuse to hear!
A good exposition of Rev. 15:1 is in a tape recording of E Alexander, preaching through the entire Book of Revelation (in The Tron church, Glasgow, as a Reformed Presbyterian) http://tapesfromscotland.org/catalogue/index.php?speakerSelect=EAlexander This verse is in his Series 27 (Revelation). Scroll down to ch. 15 and click the link. Do listen to at least 12 mins. 30 seconds into the sermon.
The clearest embracing of verse 1 I have come across is from the Trinitarian Protestant source you mention. The seventh angel pours out the final plague from heaven on the world, with the final, last trump, heralding the wrapping up of all things at the terrifyingly glorious appearing of Christ to usher in the Day of Resurrection and Judgment. Because God's wrath has now been fully expressed, he is satisfied that now can be the cosmic removal of the universe, to be replaced with a new heaven and a new earth, in which righteousness will dwell (pp. 415 - 420).
