This chapter of Luke corresponds to Mat 24 and Mar 13. My comments about Mat 24 are posted here (2011) and here (2012). Matthew records three questions that the disciples ask Jesus, while Mark and Luke record two questions:
Mat 24:3 –
1) When will these things be (the throwing down of the Temple)?
2) What will be the sign of Your coming?
3) What will be the sign of the end of the age?
Luk 21:7 –
1) When will these things be (the throwing down of the Temple);
2) What sign will there be when these things are about to take place?
We discovered when we were studying Matthew, that Jesus answered all three questions recorded in Matthew as follows:
1st question in Mat 24:15-22;
2nd question in Mat 24:23-51;
3rd question in Mat 24:4-14.
So I correlated Jesus’ answers in Luke with His answers in Matthew, to see what I could discover concerning His answering of these two questions (I posted my notes; click on the link to see them). The substance of Jesus’ answer in Luke follows point for point the substance of Jesus’ answer in Matthew, so it was easy to correlate.
I have previously correlated Mar 13 to Mat 24. The same questions that Jesus answers in Mat 24, He answers in Mar 13 and Luk 21.