Acts 17:11, 13

They found that the Jews of Berea were of more noble character and much more open minded than those of Thessalonica. They were hungry to learn and eagerly received the word. Every day they opened the scrolls of Scripture to search and examine them, to verify that what Paul taught them was true.

When the news reached the Jews in Thessalonica that Paul was now in Berea, preaching the word of God, the troublemakers went there too and they agitated and stirred up the crowds against him.