Acts 18:5

‘But when Silas and Timothy came down from Macedonia, Paul was constrained by the word, testifying to the Jews that Jesus was the Christ.'

The arrival of Silas and Timothy from Macedonia, no doubt at his request, must have encouraged him, especially as they brought from Thessalonica encouraging news about the progress of the Christians there (see 1 Thessalonians 3:6), although he also learned of their problems (1 Thessalonians 2:3; 1 Thessalonians 4:13 to 1 Thessalonians 5:11). It was during this time at Corinth that he wrote the letters to the Thessalonians. Many consider that gifts from Macedonia enabled him to concentrate more time on the ministry in Corinth without looking to that church for support. He was determined not to receive any gifts or support from the church in Corinth itself. He wanted to combat their mercenary approach to life.

Heartened by the arrival of Silas and Timothy he was ‘constrained by the word', testifying to the Jews that Jesus was the Messiah. The phrase ‘constrained by the word' is a powerful one, demonstrating that the word was so pressing on him that in spite of his illness he felt that he could do nothing but proclaim it and reason from it. Thus he could later write ‘My speech and my preaching were not in persuasive words of men's wisdom, but in demonstration of the Spirit and of power' (1 Corinthians 2:4). He had become acutely aware that anyone converted in the atmosphere of Corinth would need to be strong, and he wanted to be sure that their faith did not stand in the wisdom of men but in the power of God (1 Corinthians 2:5). In his weakness the word had become his slave-master, and he was preaching with power and with urgency.