John Nelson Darby was a Dispy but he was not a Mid acts dispy. Certainly he was not the father of it.
He is however the modern day father of the pre-trib rapture, it did not originate with him, it originated with the Irvingites. Having failed to get his doctrine past the British theologians Darby took it to America where it took off like a rocket.
He did a sleight of hand.
He took the meaning of "departure" in 2nd Thess. and changed it from rebellion which had been the unanimously accepted meaning and gave it a new meaning "departure" as in "removal" i.e. the removal of the church.
This makes IMPOSSIBLE grammar. For Paul now says this
"Brethren concerning the coming of the Lord Jesus Christ and our meeting Him in the clouds I beseech you etc....
....that day cannot come unless first there has come a departure...."
So Paul according to Darby is saying
Brethren...concerning the rapture, that day cannot come until first there has come a rapture.
See how impossible that is?
It is 2 Thesslonians 1 that is about the Pre-Trib Rapture, not chapter 2.
Chapter 2 follows or builds on chapter 1 by going into events that will take place AFTER the Rapture.
Chapter 2's events will be years AFTER the Rapture, not to mention an additional, Prophetic gap, in between!
Note how much in chapter 2 is Trib info he assumes they had known the Timeline of (though, obviously from his having taught it to them at a previous time).
The chapter smacks of John chapter 5 through and through, etc.
Be warned, though; I subscribe to a Mid-Acts Hermenuetic that, while differing in key areas from that of others on here, still holds to many of their similarities.
Here is a difference I hold to - 2 Thess. 2:7's "mystery of iniquity" refers to what mystery?
To the mystery of iniquity restrained.