What does 2 Thessalonians 3:1 mean?

"Finally" in this verse introduces the final section of Paul's second letter to the believers at Thessalonica. He asks for prayer for his coworkers and himself. It is an especially selfless prayer request, because Paul doesn't ask for his financial needs to be met or for his health needs. He asks for prayer on behalf of his group's proclamation of God's Word. Specifically, he asks for prayer that the Word may have free course and be acknowledged as God's authoritative, powerful Word. That is how the Thessalonians had received it.

Paul recognized two things. He recognized that his ministry could not succeed without prayer, and he recognized that God's Word was effective. In Romans 1:16 he testifies, "I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek." It was this confidence in the power of God's message that drove him to proclaim it throughout the Roman Empire.