The gospel is moving in all directions: the folks in Jerusalem are embracing it; Jews in other cities embrace it; Gentiles begin embracing it; and the whole movement looks like the work of God to save through Messiah Jesus, the Lord of all. Alongside this work is the work of prophets, early messianic prophets:
11:27 At that time some prophets came down from Jerusalem to Antioch. 11:28 One of them, named Agabus, got up and predicted by the Spirit that a severe famine was about to come over the whole inhabited world. (This took place during the reign of Claudius.) 11:29 So the disciples, each in accordance with his financial ability, decided to send relief to the brothers living in Judea. 11:30 They did so, sending their financial aid to the elders by Barnabas and Saul.
The prophet Agabus announces that a famine will cover the whole inhabited world, which Luke adds did take place under Claudius, and the response is that each person — as he was able — send relief to the messianists in Jerusalem.