The Thessalonian epistles are a tremendous study in eschatology.
Just as the Olivet discourse is Christ's exposition of His second coming and the events that are associated with it, 1st and 2nd Thessalonians are Paul's treatise on the same subject.
The setting for the epistles is Paul's great concern for the newly formed church in Thessalonica. Upon leaving Philippi due to the intensification of the persecution there, Paul travels to Thessalonica where it appears he spent 3 weeks or more and saw many come to believe upon Jesus. When the persecution there became sharp he was sent away by the new believers. Some relatively short time later from Athens, Paul sends Timothy to them to check on them. Timothy returns when Paul is in Corinth and reports on their state. Paul learns of the severe persecution these new believers were facing from their own countrymen. It is Paul's concern that the Thessalonians be equipped to be overcomers in the midst of tribulation; that is the impetus of Paul's epistle.
The best encouragement that a persecuted believer can have is knowing with certainty that Christ is coming again to receive him or her to Himself.
Paul's focus throughout these two epistles is that second coming of Christ.
Notice all the references made to the Lord's coming.
1Th 1:10 And to wait for his Son from heaven, whom he raised from the dead, even Jesus, which delivered us from the wrath to come.
1Th 2:19 For what is our hope, or joy, or crown of rejoicing? Are not even ye in the presence of our Lord Jesus Christ at his coming?
1Th 3:13 To the end he may stablish your hearts unblameable in holiness before God, even our Father, at the coming of our Lord Jesus Christ with all his saints.
1Th 4:15 For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.
1Th 5:2 For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
1Th 5:23 And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
2Th 1:7 And to you who are troubled rest with us, when the Lord Jesus shall be revealed from heaven with his mighty angels, ...
2Th 1:10 When he shall come to be glorified in his saints, and to be admired in all them that believe (because our testimony among you was believed) in that day.
2Th 2:1 Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him,
2Th 2:8 And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming:
2Th 3:5 And the Lord direct your hearts into the love of God, and into the patient waiting for Christ.
The epistle, essentially written to encourage the persecuted saints in Thessalonica, presents many details concerning the coming (parousia) of Christ.
Parousia means arrival and continuing presence.
1) The parousia will involve Christ coming with the holy angels into the atmospheric heaven (1Thes 4:17; 2Thes 1:7).
2) The parousia will involve Christ being revealed from heaven (2Thes 1:7).
3) The parousia will involve unbelievers being caught unawares (1Thes 5:2-3).
4) The parousia will be expected by the church, which shall not be caught unawares (1Thes 5:4-5).
5) The parousia of Christ will involve the resurrection of the dead in Christ (1Thes 4:13-16).
6) The parousia of Christ will involve the church being gathered to Christ in the clouds (1Thes 4:17; 2Thes 2:1).
7) The parousia of Christ will initiate the day of the Lord (1Thes 5:2-3; 2Thes 1:6-10; 2Thes 2:1-2).
8) The church is said to not be appointed unto God's wrath upon the day of the Lord (1Thes 1:10; 5:9, 2-3).
9) The church shall rest from persecution when Christ and the mighty angels are revealed on the day of the Lord bringing tribulation upon the wicked (2Thes 1:6-10).
10) The day of Christ which involves Christ's parousia and our gathering together unto Him is said that it will not come until a notable departure from the faith (falling away) and the man of sin (the Beast) is revealed by shewing himself to be God in the rebuilt temple (2Thes 2:1-4).
Paul agrees with Jesus, John, and Daniel that the unprecedented persecution comes, before the rescue of the church, which takes place earlier upon the same day, when God's wrath begins to be poured out upon the wicked earth-dwellers, who are and shall be our persecutors.
All praise, honour, and glory be unto the Lord Jesus Christ.