In verse 6, God will do two things: he will pay back trouble to those who trouble you and he will give relief to you who are troubled.
The answer as to what this "pay back" looks like and this "relief" looks like is found in verses 9 and 10.
Pay back = being punished with everlasting destruction and being shut out from the presence of the Lord and from the majesty of his power.
Relief = Jesus coming to be glorified in his holy people and to be marveled at among all those who have believed. This includes you, because you have believed our testimony to you.
Both the "pay back" and the "relief" occur at the same time - on that day!
So far, so good. On this we are actually agreed: Pay back and relief happen at the same time.
But I believe that you are still missing the pointed Thessalonian application. This was, after all, a real letter written to Christians who were suffering terribly at the hands of the Jews (as we read in Acts). To these first-century Thessalonians, gathered together to have Paul's personal letter written to them, Paul had personally, by inspiration, promised relief. The relief was not that everything will be rewarded in the end. (Yes, I know that there verses that also teach this truth.)
According to your view (the common view), actually, they would really get no timely relief. They would all die before justice was done.
What the Thessalonian church received from Paul was a promise that God is just - those who persecute the church will be shut out from the presence of God.
They will be punished with everlasting destruction. Those who believe will be included in the holy ones when Jesus comes to be glorified in his holy people.
You make it too general. Read this letter with Thessalonian eyes, not only modern ones. That hard to have been real relief for them. And, historically and scripturally, there was.
The emotional and spiritual impact of this promise forms the foundation for Paul urging them to continue to stand firm - an eternal encouragement and good hope, encouraging and strengthening them and us in every good deed and word (2:16-17).
The promise was a real one. That was the impact.
The question you posed is rather easy to answer from the context of the passage. There is more to life than your present sufferings. God is just. He will pay back trouble to those who trouble you. He will grant relief to those who are persecuted. When? When Jesus Christ is revealed from heaven . . . on that day! Paul is giving them an eternal perspective for a temporal problem!!! Since there is more to life than our present sufferings, stand firm (2:15).
But nowhere in this letter does Paul tell them these things. The stand fast of the next chapter was that they wold not fall for the delusions and false teachings (see the verses just before).
Take a look again at this passage. I emphasized a few things:
3 We are bound to thank God always for you, brethren, as it is fitting, because your faith grows exceedingly, and the love of every one of you all abounds toward each other,
4 so that we ourselves boast of you among the churches of God for your patience and faith in all your persecutions and tribulations that you endure,
5 which is manifest evidence of the righteous judgment of God, that you may be counted worthy of the kingdom of God, for which you also suffer;
6 since it is a righteous thing with God to repay with tribulation those who trouble you, [/quote]
Right here is the payback. And it is not a "To whom it concerns". The payback falls right on the ones troubling the Thessalonians - the unbelieving Jews, the very ones who dogged every step of the apostles.1 Thess. 2:14 - 16 speaks more on this.
How are these Jews paid back? When Christ comes to Jerusalem He comes right when Jerusalem is filled to capacity, because of the Passover, with Jews from all over the kingdom. They become, per Jesus' prophecy, trapped.
The ones who gave the Thessalonians such grief are themselves destroyed, brought into captivity. They are no longer able to persecute - empire-wide.
7 and to give you who are troubled rest with us when the Lord Jesus is revealed from heaven with His mighty angels,
8 in flaming fire taking vengeance on those who do not know God, and on those who do not obey the gospel of our Lord Jesus Christ.
9 These shall be punished with everlasting destruction from the presence of the Lord and from the glory of His power,
10 when He comes, in that Day, to be glorified in His saints and to be admired among all those who believe, because our testimony among you was believed.
All of the above is the same event, written in apocalyptical language, which is common in the Old Testament.
Christ's coming took them unawares. They did not see it, just as they did not see Elijah's coming in the form of John the Baptist. Though wisdom is justified by her children.