Matthew 24:16

“Then let those who are in Judaea flee to the mountains,”

And when the people of Judaea saw the danger of the armies of Rome surrounding Jerusalem they were to flee to the mountains, for the Roman search parties foraging for food would be a danger to all Jews, and once the city had fallen vengeance and reprisals would be wreaked on the whole surrounding area. The purpose of fleeing into the mountains was in order to escape the ‘great tribulation' which was coming on those who did not flee, which serves to demonstrate that those who would suffer under the tribulation would be localised. Sadly many instead fled into the city itself, so that many from Judaea were found in the city when it was taken, thus experiencing the initial phases of their great tribulation, and being subjected to the remainder.

However Eusebius tells us that the Romans allowed those who wished to leave the city, prior to its final investment, to do so (when his spies told him of all the atrocities of Jew against Jew that were going on in Jerusalem he might well have done so). If this be so then it was also open to them to flee to the mountains had they wished to do so. This ‘fleeing to the mountains' has in mind what had previously happened in the time of Jeremiah (compare Jeremiah 16:16; Jeremiah 50:6; Lamentations 4:19). David had also fled from Saul into the mountains with his men. The mountains were ever a refuge from enemies and from invading hordes.

The purpose behind this description and what follows is so as to bring out the urgency of the situation and the importance of avoiding the tribulation that would ensue. (It had nothing specifically to do with Jewish Christians, although they would benefit too when they fled to Pella).