The jealousy may be due to the fact that lots of people want to hear Paul speak, similar to the jealousy of those in Jerusalem (see Acts 5:17). Quite possibly they came to realise that the good news which Paul was proclaiming permitted Gentiles to become parts of God’s people without having to adhere to old covenant civil and ceremonial laws. This would be a real threat to their religious and ethnic identity as a people.1 Alternatively, they were cautious of upsetting the political rulers in Antioch, worried that they may lose some of their freedoms if the balance of religious power was upset.2
45 But when the Jews saw the crowds, they were filled with jealousy and began to contradict what was spoken by Paul, reviling him.