Paul commends the Thessalonian church for their diligence and propensity to share the gospel in response for receiving the word of the Lord with joy. There are many natural responses to having received the gospel: turning from idols (v.9), joy from the Spirit (v.6), loving the brethren (v.3-4). But, we also see that one of the church’s responses to the gospel is to be an evangelistic witness (v.8).
If the church is to imitate Christ, just like Paul and his company did, then its sounding forth of the gospel will not be with a begrudging word, but it will be done with much conviction and assurance through the power of the Holy Spirit. It is a zeal (that must be accompanied with knowledge) for the joy of salvation that caused the Thessalonian church to be a resounding witness, even unto their surrounding areas. Just as Christ’s gospel and its benefits were readily received, so, also, were their lives ready for a humble submission to the service and display of the gospel.