For this cause we also thank God without ceasing, that, when you received from us the word of the message of God, you accepted it not as the word of men, but, as it is in truth, the word of God, which also works in you who believe.
Paul's testimony in  1 Thessalonians 2:13 shows that Luke's account in Acts was focused upon the unbelievers in Thessalonica, whereas Paul here tells the way it was with the believers.