When you know unsustainable trouble is ahead, it is time to move to safety. The Old Testament account of the destruction of Sodom was preceded by a warning to flee from the city before they were also killed (Genesis 19:12-16).  John the Baptist exposed the religious leaders who had no intention of repenting, but came to see him baptising, by saying, "You brood of vipers! Who warned you to flee from the coming wrath?" (Matthew 3:7) ... but they were just playing religious games and did not think that God's judgement would fall on them.

In today's passage, Jesus was very specific about the catastrophic destruction of Jerusalem which happened in AD70, describing some of the coming horrors in graphic detail.  After a siege of 143 days, 30,000 Roman soldiers battered down the gates of the holy city destroying everything including the magnificent temple and killed over 600,000 people.  Jesus’ prophetic words amplified Daniel’s record of God’s Word some 500 years previously (Daniel 11:31-35; Daniel 12:11-12).  

That dreadful episode, 40 years after the crucifixion of Christ, was also symbolic of God's wrath upon all who reject Jesus Christ at the Last Day (Romans 2:5).  Those in Jerusalem, who believed in Him, were warned so that they could escape the bloodbath.  The teaching had practical significance, sparing the lives of many in the church and sending another wave of refugees into the rest of the Roman Empire, with the message of Jesus.  But not only would they be saved from death; they would also become a missionary movement, warning people to flee from God's final act of wrath upon those who reject Jesus (Malachi 3:2-4; Revelation 6:17).

The gospel continues to be both a warning that God will come in wrath upon those who resist His love, and an announcement of how to be saved (Acts 13:44-49).   Properly understood, the gospel is a movement of God's news - carried by people who have heeded His warning and found their safety in Christ.  If you have come to Jesus through its message, then you also have a responsibility to share it before He comes again and calls all people to account.