[aimhigh]

Try reading Paul's letter from that perspective.

Try reading the actual text. By context, Paul is talking about the day when Christ comes to gather the church. And he says, "that Day will not come unless the falling away comes first, and the man of sin is revealed, the son of perdition"

Context, context context.

[aimhigh]

The falling away comes first! AND the man of sin is revealed.

[MHGinTN]

2 Thess 2:1Now 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.

The CONTEXT of the second letter is addressing a lie or lies told or written to the believers telling them that the tough times and [persecution they were enduring was the proof that the great and terrible day of the Lord had arrived. The context is also what Paul had written to them previously regarding the departure of the living and dead believers.

In that context Paul is telling them that they could not have missed the departure because what follows the departure had not arrived. Context context context.