Jesus said, "This good news of the kingdom shall be proclaimed in all the world as a witness to all nations and then the end shall come" (Mt 24:14). But Revelation 14:6 says that an angel has the "everlasting gospel to preach to the world." So who exactly preaches the good news, a prophet or an angel? And most importantly of all, what is this good news of the kingdom, anyway? It's not what you think!
I received this question about Revelation 14:6 on whether angels or men will be preaching the gospel before the end:
Considering Rev 14:6..."And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people"...why do we assume that Mt 24:14 refers to man preaching the Gospel to the world? Just a question I have always wanted to ask...
I agree with my correspondent that Matthew 24:14 and Revelation 14:6 are parallel prophecies. But I don't agree with the implied conclusion that Revelation 14:6 says that an angel will accomplish this, even though it does seem to say that. For sure, decades ago before really studying the Bible in depth I would have hastily agreed with this seemingly clear or obvious meaning to the Revelation passage.
Historical Precedents of Preaching
What changed this for me being better acquainted with the Biblical precedents of how God passes his messages to humanity in general. God has always used man to preach to the masses, not angels (who seem to only appear to the righteous and in small numbers). You won't find a single case in the Bible where an angel preaches to large groups. The largest group I can think of would be the shepherds near Bethlehem who were alerted by angels to Jesus' birth (Luke 2:8-20).
I don't think Revelation 14 breaks this precedent. It never comes out explicitly saying that "and the angel preached the gospel to the world." If you read it carefully you only will find that it "has" the gospel to be preached to the world. Normally as messengers, angels deliver their messages to men who then take it to the masses.
Who these gospel-preaching-men might be in this case is perhaps answered by the immediate context. The three angels are introduced right after the 144,000  are described on Mt. Zion along with their special sealing of protection. The angels will deliver the messages to men like the 144,000, as well as other prophets before them, specifically Elijah . This for me explains the reason for the special protection on the 144,000: they have work to do in a hostile environment: proclaim the gospel to the whole world while it is under nearly complete control of the Antichrist.
Before the 144,000 Preach, "Elijah Must Come First" (Mt 17:10)
While Revelation 14 definitely implies the 144,000 preaching the gospel in all the world during the Great Tribulation, that's not where it starts. It starts even before the end, of which the Great Tribulation is the concluding part (after the "Beginning of Sorrows" ):
Matthew 24:14 (HCSB) — This good news of the kingdom will be proclaimed in all the world as a testimony to all nations. And then the end will come.
The logical choice for who will deliver this message "before the end" is the one named end time prophet: the end time Elijah prophet of Malachi 4:6. "Turning people to repentance" as it says is what the good news of the kingdom message does. It would make sense for Elijah to start this message using the Internet and then pass the baton to the 144000 when it goes down with WWIII and Wormwood  (which by no coincidence is when the 144,000 are sealed).
But notice also that the purpose of the preaching in Mt 24:14 is not to convince everyone, but to serve as a witness before judgment can come. In this way everyone who wanted to repent had the information to do so and could have done so and thus could not say they didn't know or that God is unfair to judge the earth as harshly as he will.
This underlines the fact once again that God is not trying to save everyone now. He is calling his firstfruits who have the tenacity to choose his way repeatedly against the opposition of Satan and his minions, the world, and their own nature. According to the Bible, their reward is to reign as kings and priests for 1000 years on earth before the Great Harvest "of the rest of the dead" is bought in .
But What is the "Good News of the Kingdom?"
Notice that my correspondent above did not ask me to define the Good News of the Kingdom. He probably thought he already knew what it was, assuming it to be the same "gospel about Jesus' redeeming death and resurrection" that Christianity focuses on. I used to think the same thing but then I noticed that Jesus never connected his coming death or resurrection to the gospel or good news of the kingdom.
Because Christianity focuses on another, counterfeit gospel, Jesus' original gospel of the kingdom has not been preached since the first century when his disciples he taught it to firsthand died out. The world has chiefly heard only a little about Jesus. In fact, mainly his death. Few Christians know much about Jesus' life and what he actually taught, which is where the good news message of the Kingdom of God is hidden.
What is the good news? Here's a clue. Whatever it is, Jesus said it would be "glad tidings to the poor" (Lk 4:18; 6:20; Mt 5:3) but not so much to the rich who would find it difficult to enter the kingdom because the good news would be less motivating for them (Mt 19:23=Luke 6:24). The Christian definition of the good news fails Jesus' test or parameters. Both the poor and the rich are in the same situation when they die; they need to qualify for an afterlife. So that cannot be the good news of the kingdom. It must be something else.
That something else is summed up in Matthew 6:33. If you understand that verse and all the verses related to it that flesh out the details of the good news of the kingdom, you'll see it fits the parameters Jesus gave, and is indeed extremely good news about this life for the typical poor global citizen now and especially in history hearing it. So good, that it completely transforms how we perceive this world, this life, it's purpose, what it's about, and how to go about living it. It explains why the Jerusalem church (Acts 2-5) who was taught this good news (Acts 2:42) ended up living communally and sharing with each other so that there was no one lacking among them (Act 4:34).
The good news of the kingdom is a life-changing secret today, that will be unleashed on the world later (Mt 24:14). If you wish to understand it now in depth and along with the incredible offer of help that God is literally making to all believers, please consider reading my exhaustive supporter study on good news of the kingdom. 
The End In 2026? It's Now Possible
Since learning in 2001 that Yeshua must return in a Sabbath year, I've had to rule out three Sabbath year cycle windows for the final 7 years (2003-2009, 2010-2016, 2017-2023). With the next window (2024-2030) less than 7 years away, I'm ready to share why I believe, based on the real end time sign of Mt 24:14, that this can be the one. If it is, the "birth pains" (WW3 + Wormwood, Lk 21:10-11) would hit near its middle in 2026 with Yeshua returning in 2030. Find out what's changed to convince me about 2026 and what you can do about it...