This is a good question and Scripture gives us a clear answer in Matthew 24:29-30. Those verses read: “Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken: and then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory” (NKJV). In verse 29 we learn that as soon as the 7-year tribulation period (which was prophesied in the book of Daniel and in the book of Revelation) is over, there will be amazing physical signs in the heavens heralding the coming of the Son of man. Think of it, the sun and moon will be darkened, stars shall plunge from heaven, and the heavens will be shaken. Earlier in the tribulation period, some of these same signs are seen when the sixth seal and fourth trumpet judgments take place (see Revelation 6:12 and 8:12), but not on the scale that is seen here. God is in complete control of the forces of nature and He will cause all on earth to see all these physical phenomena just before His Son appears. Verse 30 goes on to say, “And then shall appear the sign of the Son of man in heaven.” In addition to the heavenly bodies bearing witness to His coming, there will be “the sign of the Son of man.” We aren’t told exactly what “the sign” is, but those on earth will definitely know what it is. Some believe that just as a special “star” appeared at Christ’s First Advent (see Matthew 2:1-2), so there will be another star to announce His Second Coming. Others believe that it will be the “Shekinah glory cloud” which was the sign of God’s presence in the Old Testament (see Exodus 13:20-23 and 1st Kings 8:11). This may be the same the cloud spoken of when Christ ascended back to heaven, as we see in Acts 1:9: “Now when He had spoken these things, while they watched, He was taken up, and A CLOUD received Him out of their sight.”

I would also like us to see what event is happening ON EARTH at the coming of the Son of Man. In Revelation 19 the apostle John had a vision of the Second Coming of Christ. Verses 11 & 15 tell us, “Now I saw heaven opened, and behold, a white horse. And He who sat on him was called Faithful and True, and in righteousness He judges and makes war….Now out of His mouth goes a sharp sword, that with it He should strike the nations.” John beheld the Lord Jesus as one who “judges and makes war” and who will “strike the nations.’ Who are these nations? Verse 19 supplies the answer: “And I saw the beast, and the kings of the earth, and their armies, gathered together to make war against Him who sat on the horse and His army.” They are the nations from all around the world! We learn more about them in Revelation 16:12-14, 16: “Then the sixth angel poured out his bowl on the great river Euphrates, and its water was dried up, so that the way of the KINGS OF THE EAST might be prepared. And I saw three unclean spirits like frogs coming out of the mouth of the dragon, out of the mouth of THE BEAST, and out of the mouth of the FALSE PROPHET…which go out to THE KINGS OF THE EARTH AND OF THE WHOLE WORLD, to gather them to THE BATTLE OF THAT GREAT DAY of God Almighty…and they gathered them together to THE PLACE CALLED IN HEBREW, ARMAGEDDON.” Satan will gather the nations from the east and the west for the infamous “battle of Armageddon.” We believe they will be gathered to do battle against one another, but once they see the heavens opened and the Son of Man coming they will join forces and “make war against Him.” They will not even fire a shot for we read in Revelation 19:20-21, “Then the beast was captured, and with him the false prophet…these two were cast alive into the lake of fire…and the rest were killed with the sword which proceeded from the mouth of Him who sat on the horse.” Man’s final rebellion against God and His Son will be crushed immediately and then the Lord Jesus will set up His glorious kingdom on earth for 1,000 years (see Revelation 20:1-6). (234.1) (DO)