What does Matthew 24:18 mean?

With startling language, Jesus is describing how quickly those in Jerusalem will need to flee when the temple is desecrated in fulfillment of Daniel's prophecy (Matthew 24:15; Daniel 9:27). The picture He paints suggests an army closing quickly on Jerusalem or about to begin a siege. Jesus has said that those on their rooftops should make a run for it without even going back into their homes to grab some possessions (Matthew 24:17). Now He adds that a person in the field should not run first toward the city to grab his cloak. There won't be time.

Jesus spoke these words to His disciples some 35 or 40 years before the temple was desecrated and destroyed. Jewish hardliners killed moderate Jewish priests, spilling their blood in the temple. Soon, Roman troops set up a siege against the city, eventually destroying Jerusalem and the temple and raining down on violence on the citizens who were unable to escape Jerusalem in time. Those events have led some Bible teachers to believe those events completely fulfilled Jesus' warning in these verses.

Given the context of an end-of-days timeline (Matthew 24:14) and the world-threatening severity of these events (Matthew 24:21–22), it's more reasonable to see AD 70 as a precursor to a final fulfillment of Jesus' words at the end of the age.