In 1 Thess. 4:13-18, isn't the ‘we’ the Thessalonians in the first century? And in 1Cor. 15:23-28 Paul is speaking to the Corinthians in their time? So shouldn't the timing and the immediate audience relevance determine the nature of the Christ coming?
Below is my response.
Of course "we" in 1Thessalonians refers to 1st century Christians. But does it refer only to 1st century Christians? Only 1st century Christians get to be "always with the Lord"? (How hopeless and futile such a position is!)
Thankfully, Paul is not teaching that only 1st century Christians will be forever with the Lord. Rather, all Christians will be with Christ forever.
"We" and "them" has regards to those who are alive and those who are dead at the time of Christ's Second Coming. There's no textual or linguistic (or theological) reason to limit "we" to 1st century Christians.
Notice in 1Cor. 6:14 Paul speaks of being among those who are dead (as opposed to alive) at Christ's Second coming.
And God both raised up the Lord and will also raise us up by His power.
Would you have us believe that ONLY 1st century Christians ("us") will be resurrected from the dead? (I sincerely hope not!)
And what of 2Cor. 4:14?
"He who raised up the Lord Jesus will also raise us up with Jesus and will present us with you."
Only 1st century Christians ("us" and "you") are raised from the dead? Surely not!
When it comes to the Second Coming, Paul speaks of "we" being alive and "us" being dead. He is not contradicting himself. This is simply the way WE talk. (For example, I can speak of how we won the War for Independence and how some believe that one day Mars will be a home for us.)
In other words, there's no reason whatsoever (linguistic or theological) to limit the hope of the resurrection and being forever with Jesus to 1st century believers.