The Great Falling Away and the Man of Sin (part 1)

Now, brothers, concerning the coming of our Lord Jesus Christ and our gathering together to Him, we beseech you, (2Thess 2:1)
not to be quickly shaken from your mind, nor be disturbed, neither by spirit nor by word nor by letter, as if from us, as though the day of Christ has come. (2Thess 2:2)
Let no one deceive you by any means; for that day will not come unless the falling away comes first, and the man of sin is unveiled, the son of perdition, (2Thess 2:3)