Paul takes action to find out about their faithfulness (1 Thess. 3:1-2)
Paul was willing to make sacrifices in his current ministry at Corinth in order to ensure the strenghtening of the Thessalonians' understanding of the truths of God's Word.
At great cost to Paul, Timothy was sent to strengthen (staridzo, firmly fix in place) their understanding and faithfulness to the truth.
Paul reminds them that affliction is part of every believer's experience (1 Thess. 3:3-4)
Affliction can raise doubts about the truth of Christianity. However, they had been eye-witnesses to the truth of Paul's teaching that opposition is to be expected from unbelievers.
Believers are destined (to be set, laid to rest, or placed by fixed law) for pressure from a world system that is hostile to God.
The tempter is creative in attacking the work of God in the life of every believer (1 Thess. 3:5)
Satan uses many methods for prying believers away from the truth: unsaved friends, false teachers, or the severity of suffering to name just a few.
These attacks are not reserved only for ministers (see 1 Thess. 2:18), but they are also directed at those being ministered to by others.
Paul is comforted by the good news and can resume his life and ministry without distraction (1 Thess. 3:6-8)
Ministers certainly need encouragement, and the best kind of encouragement is knowing that those to whom they have ministered are walking steadfastly in the faith.
Paul desires to complete what is lacking in their faith (1 Thess. 3:9-10)
This does not mean that their initial trust in Christ for salvation was lacking in any way.
Paul's focus is that their understanding of the truths of The Faith should increase, and that their faithfulness to these truths should not waver under persecution.
Paul simply wants to complete his ministry of bringing these new believers to full maturity in Christ.
Paul's two-part prayer (1 Thess. 3:11-13)
Paul prays for himself, that the Lord would allow him to complete his ministry with them.
Paul prays for them, that they would increase in self-sacrificing love for each other and everyone else.
This increase in love will produce increasing holiness of life. More of the fruit of the Spirit will be evident in their lives. There will be no cause for blame when they stand before the Judgment Seat of Christ.
In the context of this epistle, the coming of the Lord Jesus would be His coming in the clouds at the Rapture of the Church. "With all His saints" (NASB) is literally "holy ones." In the New Testament, this phrase is never used to refer to angels unless it is accompanied by the word "angels" (angeloi), so the translators of the NASB have correctly rendered it "saints," referring to the souls of the believing dead who will precede those who are left alive at Christ's coming for the Church. When "we who are alive and remain until the coming of the Lord" (1 Thess. 4:15) finally arrive in the clouds to meet the Lord, He will have with Him all His saints -- "God will bring with Him those who have fallen asleep in Jesus" (1 Thess. 4:14).
Points of Application:
God views the ministry of encouraging the faith of others to be of first importance. Some of us might be a "Timothy" that God could send to build up other believers.
We should not be surprised if persecution or affliction comes into our lives, and we must be aware of the schemes of the tempter who wants us to abandon the truth of God's Word.
We should follow the prompting of God's Spirit to continually increase and abound in the kind of self-sacrificing love that leads to holiness of life, looking forward to the day when we will be able to stand before the Judgment Seat of Christ after the glorious Rapture of the Church.