There must have been serious questions in Paul’s mind concerning the long-term viability of the church in Thessalonica. The church had barely been formed before Paul and Silas had to move on to Berea due to great opposition (see Acts 17:1-10). This fledgling young church was left in a hostile environment, without anyone obviously qualified to be their pastor, and reliant on a very brief (but intensive) period of teaching from Paul for their Christian doctrine.

Hence there is a strong theme of perseverance running through 1 Thessalonians (and 2 Thess, although I have mainly used examples from 1 Thess). Paul fears that the devil may tempt them to fall away, yet at the same time he has confidence in God’s power to sustain them. This is the paradox of perseverance for Paul – it is assured, but not automatic. His confidence in God does not lead him to be casual about continuing in the faith.

Perseverance is assured

Several verses in 1 Thessalonians demonstrate Paul’s confidence in God to sustain the believers despite the attacks on their faith. He has seen in the work of the Spirit amongst them evidence that they have been chosen (1:4,5). He knows that his evangelism there was not in vain (2:1). The believers do not stand firm in their own strength, but in the Lord (3:8). He knows that their final destiny is not wrath, but salvation (5:9). Ultimately, their perseverance depends on God’s faithfulness, hence it is sure (5:24, 2 Thess 3:3).

Perseverance is not automatic.

Yet, despite this confidence in the faithfulness of God, Paul was greatly concerned, even fearful, that the devil could have got in, and everything that had been done would end up have being “in vain” (3:5). In particular, he knew that suffering and persecution, could be causes of failure to persevere (3:4). It was therefore a source of overwhelming joy and relief for Paul to discover that the Thessalonians were in fact standing firm (3:7-10). He also recognises that he himself cannot presume on his own strength and is also in need of prayer (5:25).

Perseverance is through means of grace

So if perseverance is not automatic, how is it obtained? Paul sees three things as being crucial means of grace, by which God has ordained to keep his people close to himself..

First is constant and persistent prayer on behalf of others. Several times in the letter he expresses his continual prayers for them (1:2, 3:10) as well as encouraging them to be constantly in prayer (5:17) themselves. When he expresses the content of his prayers, it is that they will continually grow in love and holiness, and most importantly, that they will be blameless on the day of the coming of Christ (3:12-13). In other words, he prays that they will not just keep going until the end, but that they would keep growing until the end.

Second is the importance of encouragement and exhortations. This was Paul’s regular practice with all the churches he founded or visited (e.g. Acts 14:22). He did not just “teach” them, but got alongside them and urged them onwards. He was like a father in the way he lovingly but firmly encouraged them (2:11,12). Several times in the letter he urges them to keep going (e.g. 4:1). He expects that there should be constant progress in the Christian walk (4:10). Like riding a bike, forward motion is what will keep you from falling. Paul also calls all the whole community of believers to play an active role in encouraging one another to continue in the faith (5:11).

Third, and most importantly, though it is only obliquely referred to in this letter, through the work of the Spirit. It is God’s work to sanctify us (5:23), which he does through the Spirit who is the one who empowers us to live in purity (4:7-8). Indeed, he understands the sanctifying work of the Spirit to be a crucial component of our salvation (2 Thess 2:13)