As Paul expresses his admiration for the example of the Thessalonians, he expresses the part the gospel played in their good conduct.
The gospel first of all showed Paul and his companions to be legitimate servants of God. The demonstration of power, given through the intervention of the Holy Spirit allowed those who heard Paul to acknowledge his legitimacy as an apostle.
“Then all the multitude kept silent and listened to Barnabas and Paul declaring how many miracles and wonders God had worked through them among the Gentiles” (Acts 15:12).
Additionally, there was power in the words themselves because they were inspired, from the Holy Spirit. They did not originate from Paul himself (2 Peter 3:16).
Their acceptance of the gospel was not without cost, as Paul notes they were afflicted for their faith. Regardless, they were joyful in their service (Galatians 5:22-23). And, their steadfastness in faith served as a wonderful example to other Christians.
