We see Paul plant the church in Thessalonica in Acts 17; however, one of the most amazing stories in all of Scripture took place in Acts 16. Paul and Silas were in Philippi preaching the gospel and planting a church and eventually ending up in prison.

Acts 16:  16-40:
“Once when we were going to the place of prayer, we were met by a female slave who had a spirit by which she predicted the future. She earned a great deal of money for her owners by fortune-telling. 17 She followed Paul and the rest of us, shouting, “These men are servants of the Most High God, who are telling you the way to be saved.” 18 She kept this up for many days. Finally Paul became so annoyed that he turned around and said to the spirit, “In the name of Jesus Christ I command you to come out of her!” At that moment the spirit left her.
19 When her owners realized that their hope of making money was gone, they seized Paul and Silas and dragged them into the marketplace to face the authorities. 20 They brought them before the magistrates and said, “These men are Jews, and are throwing our city into an uproar 21 by advocating customs unlawful for us Romans to accept or practice.”
22 The crowd joined in the attack against Paul and Silas, and the magistrates ordered them to be stripped and beaten with rods. 23 After they had been severely flogged, they were thrown into prison, and the jailer was commanded to guard them carefully. 24 When he received these orders, he put them in the inner cell and fastened their feet in the stocks.
25 About midnight Paul and Silas were praying and singing hymns to God, and the other prisoners were listening to them. 26 Suddenly there was such a violent earthquake that the foundations of the prison were shaken. At once all the prison doors flew open, and everyone’s chains came loose. 27 The jailer woke up, and when he saw the prison doors open, he drew his sword and was about to kill himself because he thought the prisoners had escaped. 28 But Paul shouted, “Don’t harm yourself! We are all here!”
29 The jailer called for lights, rushed in and fell trembling before Paul and Silas. 30 He then brought them out and asked, “Sirs, what must I do to be saved?”
31 They replied, “Believe in the Lord Jesus, and you will be saved—you and your household.” 32 Then they spoke the word of the Lord to him and to all the others in his house. 33 At that hour of the night the jailer took them and washed their wounds; then immediately he and all his household were baptized. 34 The jailer brought them into his house and set a meal before them; he was filled with joy because he had come to believe in God—he and his whole household.
35 When it was daylight, the magistrates sent their officers to the jailer with the order: “Release those men.” 36 The jailer told Paul, “The magistrates have ordered that you and Silas be released. Now you can leave. Go in peace.”
37 But Paul said to the officers: “They beat us publicly without a trial, even though we are Roman citizens, and threw us into prison. And now do they want to get rid of us quietly? No! Let them come themselves and escort us out.”
38 The officers reported this to the magistrates, and when they heard that Paul and Silas were Roman citizens, they were alarmed. 39 They came to appease them and escorted them from the prison, requesting them to leave the city. 40 After Paul and Silas came out of the prison, they went to Lydia’s house, where they met with the brothers and sisters and encouraged them. Then they left.”

Those last words of verse 40 say a lot! “Then they left.” They left, but they did not quit. Their very next stop along the path was Thessalonica. We find that story in Acts 17:
When Paul and his companions had passed through Amphipolis and Apollonia, they came to Thessalonica, where there was a Jewish synagogue. 2 As was his custom, Paul went into the synagogue, and on three Sabbath days he reasoned with them from the Scriptures, 3 explaining and proving that the Messiah had to suffer and rise from the dead. “This Jesus I am proclaiming to you is the Messiah,” he said. 4 Some of the Jews were persuaded and joined Paul and Silas, as did a large number of God-fearing Greeks and quite a few prominent women.
5 But other Jews were jealous; so they rounded up some bad characters from the marketplace, formed a mob and started a riot in the city. They rushed to Jason’s house in search of Paul and Silas in order to bring them out to the crowd. 6 But when they did not find them, they dragged Jason and some other believers before the city officials, shouting: “These men who have caused trouble all over the world have now come here, 7 and Jason has welcomed them into his house. They are all defying Caesar’s decrees, saying that there is another king, one called Jesus.” 8 When they heard this, the crowd and the city officials were thrown into turmoil. 9 Then they made Jason and the others post bond and let them go. 10 As soon as it was night, the believers sent Paul and Silas away to Berea”(Acts 17:1-10).

Notice, that Paul went into the Jewish synagogues and began to preach as soon as he entered the city. Some Jews and Greeks accepted the Gospel, and a church was planted. Many others rejected the gospel and in just a few weeks Paul was forced out of town and headed to Berea. However, the believers that remained, made up of both Jews and Greeks, formed a church that Paul would refer to as a MODEL for other churches and believers to follow (1 Thessalonians 1:7).