What ! Answer to # 2
2nd Thessalonians 2:1-3
1Now concerning the coming of our Lord Jesus Christ and our being
gathered together to him, we ask you, brothers,
a 2not to be quickly shaken in mind or alarmed, either by a spirit or a spoken word, or a letter seeming to be from us, to the effect that the day of the Lord has come.
3Let no one deceive you in any way. For that day will not come, unless the rebellion comes first, and the man of lawlessness
b is revealed, the son of destruction,
That's exactly what he's talking about ! The "gathering" won't happen until the "falling away" happens first.
Answer #1
It's obvious because of Vs 1. The coming of the Lord and our gathering unto him. This is exactly the timeline Jesus gave in the Olivet Discourse.
Question for you : What did the Jews have to "fall away" from ? They had already rejected Jesus. The gathering of the Elect didn't happen in 70 AD. No one sat in the Temple declaring himself God, they burnt the Temple, then pushed the stones down to retrieve the melted gold.