Albert Barnes Commentary Acts 21:34

"And some shouted one thing, some another, among the crowd: and when he could not know the certainty for the uproar, he commanded him to be brought into the castle." — Acts 21:34 (ASV)

Into the castle. The castle or tower of Antonia, where the guard was kept.

See Barnes on Acts 21:31.

Compare to Acts 23:10, 16.