I Thessalonians 1:8, 9

"You have trumpeted out the word of the Lord not only in Greece but all over the place. Your trust in God is being discussed all over the place. I do not even need to tell anyone about you, they already know." (I Thessalonians 1:8)

The testimony of this church had spread rapidly. It is believed that even in Rome, people had heard of these believers. Their faith was being talked about.

"They tell me about what happened when we arrived in Thessalonica. How you turned from dead idols to become willing slaves of the living God." (I Thessalonians 1:9)

People knew about how the word arrived in Thessalonica. People knew about the conversion of these believers from idolatry to Christian faith. They were serving the Lord.