Paul, Silas, and Timothy brought the gospel message to the ancient city of Thessalonica, and it had a massive impact on the city. Acts 17:4 states that "a great multitude" received the gospel message resulting in a church being planted. Persecution quickly arose, and after only about three weeks Paul, Silas, and Timothy had to leave this fledgling church. The hearts and minds of these three men were perpetually concerned for the state of these new believers in Jesus. So they write a letter to establish and encourage them in the faith.