What does Acts 21:32 mean?
Jews from Asia, a large province in western modern-day Turkey, previously saw Paul in Jerusalem with Trophimus, an Asian Gentile. When they later see Paul in the temple, they erroneously assume Paul brought Trophimus inside with him. That would be considered a religious offense, and punishable under Roman law. The accusers rile up the crowd of worshipers who promptly drag Paul out of the temple, shut the gates, and beat him. Before they can kill him, the Roman tribune hears of the commotion and intervenes (Acts 21:23–31).The tribune is probably not yet thirty years old, likely a young senator taking a year to learn more about the Empire. That experience comes by providing administration and leadership for the Roman army's outpost in Jerusalem. The centurions are army officers in command of about 100 legionaries; about 600 soldiers live in barracks in Jerusalem.
The governor is in Caesarea Maritima, sixty miles away. Jerusalem is rather notorious for civil unrest. A Roman leader who loses control of Jerusalem may face dismissal—as Pilate discovered some time after his experience with Jesus. The tribune needs to stop the riot and extricate Paul from their grasp. However, he needs to accomplish this without such a show of strength the crowd will feel threatened. Then he needs to take Paul into the barracks to interrogate him and determine what is going on.
Acts 21:27–36 explains why Paul's public ministry takes a five-year hiatus. He has arrived in Jerusalem only to hear a rumor that he abandoned the Mosaic law. Seeking to prove otherwise, he is then slandered with a rumor that he brought a Gentile into the temple. Before the mob can kill him, the Roman tribune takes him into custody. He will face two years house arrest in Caesarea Maritima and two in Rome, broken up by a dangerous sea voyage that ends in a shipwreck. But he will also be able to share Jesus' story with audiences he never dreamed of. These include a king and Caesar's own household.
In Acts 21, Paul returns to Judea from his third missionary journey and promptly gets arrested. He begins by visiting Philip in Caesarea Maritima. Church elders in Jerusalem ask Paul to help men fulfill a Nazirite vow, to dispel rumors he has apostatized his Jewishness. While doing so, Ephesian Jews accuse Paul of bringing one of his Gentile Ephesian companions into the temple. The Roman military tribune keeps the enraged crowd from tearing Paul limb from limb by arresting him.