Here, in one chapter, John sees 3 visions describing signs that span whole 7-year tribulation.
In the first vision, John sees the 144000 born again Jews we met in chapter 7v2-4: "Then I saw another angel ascending from the rising of the sun, with the seal of the living God, and he called with a loud voice to the four angels who had been given power to harm earth and sea, saying, “Do not harm the earth or the sea or the trees, until we have sealed the servants of our God on their foreheads.” And I heard the number of the sealed, 144,000, sealed from every tribe of the sons of Israel:..." Now we see them with the Lord chapter 14:1 "Then I looked, and behold, on Mount Zion stood the Lamb, and with him 144,000 who had his name and his Father's name written on their foreheads." There are many opinions on which "Mount Zion" this is. We know there is one on earth in Israel and one in heaven. I believe it is the one in heaven.
I believe this symbolically represents the revival during early tribulation and the promised salvation of the (remnant of) Jewish nation.
The second vision reveals 3 angels making proclamations " ... to those who dwell on earth, to every nation and tribe and language and people." So EVERYONE will hear dire their warnings and I don't see how the could NOT KNOW they are from God.
This vision symbolizes God's practice, seen throughout all scripture, to give warning before judgement.
The third vision is the judgement from God warned about by the three angels i the previous vision. This is our first glimpse of Armageddon, symbolized in two harvests. The first is the "wheat" harvest of the last souls on earth who are to be saved, with the sickle swung by Jesus Himself. The second harvest uses the well stablished metaphor of wine representing blood. 14:19-20 "So the angel swung his sickle across the earth and gathered the grape harvest of the earth and threw it into the great winepress of the wrath of God. And the winepress was trodden outside the city, and blood flowed from the winepress, as high as a horse's bridle, for 1,600 stadia." This is the blood of those who chose not to fear the wrath of God, and symbolizes there will be A LOT of it at Armageddon.
We covered this in detail in two parts.
Revelation 14 Part 1 Video
Revelation 14 Part 1 PowerPoint
Revelation 14 Part 1 Video
Revelation 14 Part 1 PowerPoint