John Gill Commentary Acts 21:10

"And as we tarried there some days, there came down from Judaea a certain prophet, named Agabus." — Acts 21:10 (ASV)

And as we tarried there many days

How many days is not said, it could not be very many, if the apostle got to Jerusalem by Pentecost, as he desired, (Acts 20:6Acts 20:15Acts 20:16) (Acts 21:4Acts 21:7)

there came down from Judea a certain prophet named Agabus ;

of whom mention is made in (Acts 11:28) who is there said to come from Jerusalem, to Antioch, and here from Judea to Caesarea; he had been many years going about from place to place prophesying, for between that and this account must be a space of about sixteen or seventeen years.