On his website, Arminian Perspectives, Ben Henshaw has a questions page at which he answers questions about Arminianism and Calvinism that visitors to his site pose in the comment section of the page. The following is a question and answer interaction between Ben and a commenter named William:
The Question Part 1: How does the Arminian understanding of soteriology deal with the text of 1 Thessalonians 1:2-4?
The Answer Part 1: What do you see in this passage that is supposed to be challenging to Arminian soteriology?
The Question Part 2: I suppose the notion of Paul being certain God had chosen them because of the power of the Spirit resulting from the gospel?
The Answer Part 2: Thanks for the clarification. You wrote,
I suppose the notion of Paul being certain God had chosen them because of the power of the Spirit resulting from the gospel?
…or their receiving the message with joy, i.e. because they believed the gospel? (verse 6)
Verses 6-10 are a continuation of Paul’s expression of confidence in verses 4 and 5, and clarify that Paul’s confidence in their election was based on their receiving the gospel in faith and demonstrating this faith through faithful service. This perfectly fits an Arminian soteriology which teaches that election is conditional on being joined to Christ (the “elect One”), and that the condition for being joined to Christ is faith.
The great conviction, or assurance, could mean several things. It could be that the apostle’s preaching was full of conviction (i.e. they preached with great confidence in the message, and that message was confirmed with demonstrations of power). It could mean that the Thessalonians received the message as a direct result of the Spirit’s conviction (though this would not necessitate that the conviction caused their faith irresistibly). It could mean that the apostle’s assurance or conviction of the effectiveness of the gospel, was simply that they believed (i.e. received the message in the joy of the Spirit; became imitators of the apostle’s faith and service; turned from idols to serve the living and true God, and to wait for His Son from heaven who rescues them from the coming wrath, etc.).
The main point is that there is nothing in this passage that necessitates an unconditional election interpretation. A Calvinist could read that into the text, but the passage alone can be easily understood in ways that are in perfect harmony with Arminian soteriology.
BTW, Calvinists contend that election cannot be certain until one perseveres to the end in saving faith. They maintain that many seem to receive the gospel and even live with impressive testimonies, but ultimately prove that they were never elect when they eventually fall away. This would make it impossible for Paul to be certain of their elect status simply because they seemed to initially receive the gospel.
However, if my interpretation is correct and election is conditioned on faith union with Christ, then Paul could express confidence in their election based on their initial response to the gospel. Furthermore, if Paul had full confidence in their election based solely on their initial reception, why then does he tell them that after that event he feared that they might not have continued in the faith (3:5)?