It is written:
“Then the sign of the Son of Man will appear in heaven, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory. And He will send His angels with a great sound of a trumpet, and they will gather together His elect from the four winds, from one end of heaven to the other. (Matthew 24:30-31)
This statement of Jesus is in the context of the judgment on Jerusalem that would occur within the lifetime of those living in His day and age (Matthew 24:34). These events were fulfilled in the year 70 A.D., when the Romans destroyed the city of Jerusalem.
How do these verses fit in with the context of the destruction of Jerusalem?
First, let’s consider that this passage is talking about the “sign” of the Son of Man.
“It is important to note that “the sign” is what “shall appear.” 4 It is misleading to understand the phrase as meaning “then shall appear the Son of Man in the sky.” The Son of Man does not appear; the sign appears. 5 Then Christ defines what the sign signifies: it is the sign that the Son of Man is now in heaven. That is, this sign (whatever it is) will signify that Jesus is in heaven above —despite the Jewish authorities and rulers of the temple killing him (Matt 16: 21; 20: 18; 26: 3–4, 59, 65–66; 27: 20), sealing his tomb (27: 62–66), and denying his resurrection (28: 11–15).” (Dr. Kenneth L. Gentry, Jr., The Olivet Discourse Made Easy: You. An Understand Jesus’ Great Prophetic Discourse, 2142-2147 (Kindle Edition); Draper, VA; Apologetics Group Media)
Second, the “clouds” are a reference to clouds of judgment, brought about by the billowing smoke brought about by the destruction of cities. This was a common metaphor for Divine judgment in the Old Testament.
Genesis 19:28-Then he looked toward Sodom and Gomorrah, and toward all the land of the plain; and he saw, and behold, the smoke of the land which went up like the smoke of a furnace.
Judges 20:38-Now the appointed signal between the men of Israel and the men in ambush was that they would make a great cloud of smoke rise up from the city,
Judges 20:40-But when the cloud began to rise from the city in a column of smoke, the Benjamites looked behind them, and there was the whole city going up in smoke to heaven.
The sign of the Son of Man was the destruction of Jerusalem itself, with the clouds of the city ascending toward Heaven like in the days of the Judges.
Third, the “”tribes of the earth” had reference to the Jewish people. The only other time this Greek word is used in Matthew shows it has reference to the twelve tribes (cf. Matthew 19:28), and the Septuagint reflects this usage continually.
Fourth, the “mourning” of this passage points to the idea that the twelve tribes would mourn in sorrow for what they had done in crucifying the Messiah.
Fifth, who are the “angels” going forth with the sound of the trumpet? The word “angel” is often used in the Bible to refer to human messengers of God (cf. Matthew 11:10; Mark 1: 2; Luke 7: 24, 27; 9: 52. 2 Chron 36: 15–16; Hag 1: 13; Mal 2: 7.). The “angels” would be the messengers sent out to teach God’s Word to the lost (cf. Matthew 28:19-20; Mark 16:15-16).
All of these facts reenforce the idea that these things all took place within the lifetimes of those people in Jesus’ day and age, as He Himself declared would happen (Matthew 24:34).