What does Acts 23:9 mean?
In Jerusalem, Paul was falsely accused, both of bringing a Gentile into the temple and of teaching Jews they didn't need to circumcise their sons. He was dragged from the temple by a mob and beaten (Acts 21:20–21, 28–32). The Roman tribune saved him by arresting him but needs to know what happened and why. The mob doesn't know (Acts 21:33–34). He can't beat the truth from Paul because Paul's a Roman citizen (Acts 22:22–29). So, the tribune has brought Paul to the Sanhedrin to see if they can enlighten him (Acts 22:30).Paul tries to steer the meeting towards Jesus, so he can convince the Jewish leaders to follow Christ. As soon as he opens his mouth, he and the high priest get into a disagreement. Realizing nothing good is going to come of the situation, Paul declares—truthfully—that he is a Pharisee. He further says all the animosity is because he preaches the resurrection of the dead (Acts 23:1–7). This is a standard belief of the Pharisees, and their lawyers come to his defense.
The whole thing is rather confusing. It's unclear who originally accused Paul of teaching Jews they didn't need to circumcise their sons, but this is a long-standing issue between him and some of the Jesus-following Pharisees. Paul never taught this; he told the Gentile believers they didn't need to follow the Mosaic law, not the Jews—in fact, he circumcised Timothy whose mother was Jewish (Acts 15:1–5; 16:1–3).
The accusation that Paul brought a Gentile in to the temple was a faulty assumption of Jews from the province of Asia in southwest modern-day Turkey who saw a Gentile they knew from Ephesus with Paul in Jerusalem (Acts 21:29). Neither of these accusations have anything to do with the resurrection of the dead.
The Pharisees' suggestion that a spirit or angel spoke to Paul is probably in reference to Paul's defense before the crowd wherein he says after he saw Jesus near Damascus, he returned to Jerusalem and fell into a trance. Jesus told him to leave Jerusalem because the Jewish leaders wanted to kill him (Acts 22:17–21). But, again, this has nothing to do with the resurrection of the dead.
In fact, the only audience that dismissed Paul's teaching about the dead rising was the Greek philosophers in Athens (Acts 17:31–32). There's no indication that his Asian accusers even cared. The Sanhedrin does care, however, if that "resurrection" is of Jesus (Acts 4:18; 5:40). It looks like Paul is only bringing it up because he knows it will set the Pharisees and Sadducees in the Sanhedrin against each other and they'll forget about how he insulted the high priest. The two groups do fall into bickering, but then they conspire to have Paul killed (Acts 23:10, 12–15).
