What does Acts 21:35 mean?
To prove that he is a Jew properly respectful to Jewish law, as well as a Christian, Paul agrees to help four men complete a Nazirite vow. Meanwhile, Jews from modern-day Turkey see Paul and one of his traveling companions, who is a Gentile, together in the city. They later see Paul at the temple and assume he's brought this friend into the temple. They loudly accuse Paul of profaning the temple. A crowd forms, drags Paul into the courtyard, and attempts to beat him to death (Acts 21:27–31).The barracks of the Roman military outpost in Jerusalem sit at the northwest corner of the temple mount, overlooking much of the courtyard. News of the riot reaches the tribune; he assembles centurions and soldiers to accompany him. They manage to extricate Paul from his attackers long enough to chain him, but when asked what is going on, the crowd has more volume than information. Their rage swells again, and the soldiers arrest Paul, more or less for no reason other than to protect him from the mob (Acts 21:32–35).
When Paul came to a saving relationship with Jesus, Jesus warned him he would suffer for His cause (Acts 9:16). Over the past few months, the Holy Spirit has warned Paul he will face imprisonment and affliction in Jerusalem (Acts 20:22–23). The beatings are nothing new; Paul has been stoned before (Acts 14:19). What may hurt most is that before the crowd started punching, they dragged Paul from the temple and shut the gates.
Before Paul became a Christian, he was trained by the great Pharisee Gamaliel (Acts 22:3), "a teacher of the law held in honor by all the people" (Acts 5:34). Paul followed the Law as well as the extra-biblical teachings the scribes developed to prevent people from coming close to breaking the law. He properly honors Mosaic law, while also understanding it will not reconcile him to God. He fights against forcing the law on Gentile Christians. But the Law of Moses is an expression of his identity as a Jew called to share Jesus' offer salvation to the Gentiles.
As the soldiers drag him into a building owned by the Roman army, it takes him farther from his temple. It's unclear if he ever returns to Jerusalem. For now, however, the temple is forbidden from him.