‘And as we tarried there some days, there came down from Judaea a certain prophet, named Agabus.'
Due to having made good time they were able to stay in Caesarea for a time and have fellowship with the church here. Perhaps Paul's Gentile companions were able to have good fellowship with Cornelius and his household. And then from Judaea arrived the prophet Agabus. Predictive prophecy is relatively rare in the New Testament (it cannot be a coincidence that apart from the warnings concerning Paul little else is heard of predictive prophecy, except later by Paul and Peter, and of course John in Revelation), but Agabus appears to have been especially gifted in that direction. He was the one who had gone from Jerusalem to Syrian Antioch and had prophesied there the famine that was coming on ‘all the world' (Acts 11:28).