Then, I saw another angel flying in in the middle of the sky, having eternal good news to announce over those dwelling upon the earth and upon every ethnicity and tribe and tongue and people, saying in a mighty voice,
“Reverence God and give glory to God, because the hour of God’s judgment arrived, and fall prostrate in homage of the One having created the heaven and the earth and sea and fountains of waters.”
Revelation 14:6-7
Whatever this “eternal good news” might be, scholars from every perspective agree that it is an authentic Gospel, and not the anathema Paul warned of.
But even if we or an angel from heaven should proclaim to you a gospel contrary to what we proclaimed to you, let that one be accursed!
Paul, Galatians 1:8 (NRSV, italics mine)

Historicist
Interestingly, some scholars look to a future fulfillment, though most see this as the eighteenth century Christian religious revival in the west, called the Great Awakening (1730s and 40s). The hour of God’s judgment was poised to come against the Roman Church in the form of the French Revolution in 1789.
Preterist
The angel represents the Church, and the good news it pronounced includes God’s impending judgment on those who persecuted the Church. But the heart of this good news is about salvation, being preached throughout the known world, as Jesus prophesied.
Each part of the angel’s message corresponds to directives located in the Gospels (including Paul’s Gospel, found in Acts).
“Reverence God”
indeed, his mercy is for those who fear [reverence] him
Mary’s Magnificat, Luke 1:50 (NRSV, modifications mine)
from generation to generation.
“Give Glory to God”
In the same way, let your light shine before others, so that they may see your good works and give glory to your Father in heaven.
Jesus’s Beatitudes, Matthew 5:16, emphasis mine)
“The Hour of God’s Judgment Is Come”
Jesus answered them, “The hour has come for the Son of Man to be glorified.”
Jesus, John 12:23 (NRSV, emphasis mine)
“Worship God, the Creator”
We are mortals just like you, and we bring you good news, that you should turn from these worthless things to the living God, who made the heaven and the earth and the sea and all that is in them.
Paul, Acts 14:14 (NRSV, emphasis mine)

Futurist
Chapter 14 begins with what pertains to the Jewish world. Now, these verses shift to the rest of the non-Jewish world.
“Eternal Good News”
Scholars who are both dispensationalists* and futurist in their eschatology (theology of what comes at the end of time) struggle to interpret John’s meaning of the above phrase.
The Gospel of the Kingdom (of God, of Heaven) began to be preached by John the Baptist and continued with Jesus and His disciples during His ministry.
The Gospel of Grace is now being preached during the Age of the Church.
When the church is “Raptured” (taken up into the sky to meet Jesus in the clouds), The Gospel of the Kingdom will once again be preached. Commentators turn to these two passages to substantiate this thinking:
“And this good news of the kingdom will be proclaimed throughout the world, as a testimony to all the nations, and then the end will come.”
Jesus, Matthew 24:14 (NRSV, modifications mine)
“But I do not count my life of any value to myself, if only I may finish my course and the ministry that I received from the Lord Jesus, to testify to the good news of God’s grace.
“And now I know that none of you, among whom I have gone about proclaiming the kingdom, will ever see my face again.”
Paul, Acts 20:24-25 (NRSV, modifications mine)
So what is this “eternal good news (gospel)”?
Three ideas have come forward.

Symbolic
The word “angel” is a transliteration of the Greek word ἄγγελος | angelos, meaning “messenger” or “sent one.” In this case, the angel is symbolic of human beings who are sent to deliver the Gospel, as has always been the case since Jesus took on flesh as a human being to teach and train other human beings to deliver the good news. Therefore the eternality of the good news being preached has to do with the Gospel’s center, the Lord Jesus Christ Who is God the Son.
Synchronous
The Gospel of the Kingdom and the Gospel of Grace, though preached in different dispensations, is still at its core the same good news of salvation, of the proclamation of God’s reality and sovereignty, and of Christ’s accomplishments through the cross and resurrection. The eternal good news is the same good news throughout scripture, as it is revealed in greater detail through each era.
Satisfied
This is the entirety of the Gospel trajectory, for now the good news of God’s restoration has come. God will now establish God’s government, God’s righteousness, God’s goodness, and God’s justice throughout earth. This trajectory begins with the news of a Kingdom that will come, then that the Kingdom has arrived (at least in part), that to enter into the Kingdom comes by grace, and now that the Kingdom will be fulfilled in every way, made complete.

Not all futurist expositors are dispensationalist, and see the “eternal good news” as the same Gospel preached throughout scripture, the good news of salvation. Whatever the meaning, all scholars agree this is a continued call to repentance for the remnant left dwelling on earth.
*Dispensationalism, developed in the eighteenth century, believes there is an historical progression found in scripture that comes in stages, or “dispensations.” Each stage brings greater revelation of God and of God’s plan of salvation. There are up to seven recognized stages, as advanced by Pierre Poiret (1646-1719) in his book, “The Divine Economy.”
- Early childhood (ended in the Flood)
- Childhood (ended in Moses’ ministry)
- Boyhood (ended in Malachi)
- Youth (ended in Christ)
- Manhood (Most of the Church)
- Old age (“human decay”, meaning the last hour of the Church)
- The restoration of all things (The Millennium, includes Christ literally reigning on the Earth with Israel restored)

Spiritual
Interpreters see the angel flying around delivering this message of eternal good news as a metaphor for a concept. This is not so much the actual Gospel, but rather a wake-up call to those left living on earth: shake out of your spiritual stupor and recognize that God is coming.
God is about to establish God’s rule in all three-dimensional reality.
Not as a spiritual theory, not as a philosophy of life among many, not as a religion that one can choose not to join. Wake up and get with God before that door closes and it is too late!
“Then the kingdom of heaven will be like this.
“Ten young women took their lamps and went to meet the bridegroom.
‘Five of them were foolish, and five were wise.
“When the foolish took their lamps, they took no oil with them,but the wise took flasks of oil with their lamps. As the bridegroom was delayed, all of them became drowsy and slept. But at midnight there was a shout, ‘Look! Here is the bridegroom! Come out to meet him.’ Then all those young women got up and trimmed their lamps.
“The foolish said to the wise, ‘Give us some of your oil, for our lamps are going out.’ But the wise replied, ‘No! there will not be enough for you and for us; you had better go to the dealers and buy some for yourselves.’ And while they went to buy it, the bridegroom came, and those who were ready went with him into the wedding banquet, and the door was shut.
“Later the other young women came also, saying, ‘Lord, lord, open to us.’ But he replied, ‘Truly I tell you, I do not know you.’
“Keep awake, therefore, for you know neither the day nor the hour.”
Jesus, Matthew 25:1-13 (NRSV, modifications mine)

The four perspectives taken from Revelation: Four Views A Parallel Commentary, edited by Steve Gregg