In 1 Thessalonians 3, Paul expresses his deep concern for the Thessalonian church and his desire to strengthen their faith. He begins by expressing his joy at hearing of their faith and love, and his desire to see them grow in holiness. He then encourages them to remain steadfast in their faith, even in the face of persecution and suffering. He reminds them that God will reward them for their faithfulness, and that they should not be discouraged by their trials.
Paul then turns his attention to Timothy, whom he had sent to the Thessalonians to strengthen their faith. He expresses his joy at hearing of Timothy's success, and his gratitude for the Thessalonians' hospitality and kindness towards him. He then encourages them to continue to live in a manner worthy of the gospel, and to remain strong in their faith.
Finally, Paul expresses his desire to visit the Thessalonians again, and his hope that God will grant him the opportunity to do so. He prays that God will strengthen their hearts and grant them peace, and that they will remain faithful to the gospel.
Overall, Paul's message in 1 Thessalonians 3 is one of encouragement and hope. He reminds the Thessalonians of the importance of faithfulness and perseverance, and of the rewards that await them if they remain steadfast in their faith. He also expresses his deep concern for them and his desire to visit them again. In doing so, he provides a powerful reminder of the importance of faith and perseverance in the face of adversity.