1. Not one stone will be left on another (1-3)

The disciples were hillbillies. They were amazed by the magnificent golden dome of the Jerusalem temple at sunset. The massive stones looked like they would last forever. But Jesus taught, "Every stone will be thrown down." It meant the Jerusalem Temple would be demolished (A.D.70) like the NY Twin Towers; nothing on earth lasts forever for the end of the world will surely come when all human civilizations and Babel towers will be destroyed on judgment day. Only Jesus is the New and True temple where we can meet and worship God forever.

2. The gospel must first be preached to all nations (4-13)

To the terrified disciples, Jesus clearly answers in advance what would happen and how we should behave: Watch out for false teachers for only Jesus is the true Messiah; don't be scared by terrorism, tsunamis, earthquakes, refugees, and famines etc, for they are nothing but birth pains, good signs for new life; make use of all, even persecutions, broken family issues and all troubles as good opportunities to witness to Jesus, even to kings and governors. No matter what happens, all that we should do is preach the gospel to all nations before Jesus' second coming while leaving all other earthly things in God's hands whether they look urgent or not.