It is not clear exactly how it was revealed to Paul that he must go to Jerusalem. It could be a private revelation or the Spirit speaking to the church (Acts 13:1–3).1 Alternatively, it could be a reference to revelation that came through a prophet like Agabus (Acts 11:27–30).2 There would be no need for special revelation if he was sent by the church in Antioch to attend a general council (Acts 15:1–41),3 and this suggests that the prophecy of Agabus is in view.
2 I went up because of a revelation and set before them (though privately before those who seemed influential) the gospel that I proclaim among the Gentiles, in order to make sure I was not running or had not run in vain.