What does Acts 23:10 mean?
The Roman army tribune of Jerusalem had to rescue Paul from a murderous mob on the temple mount. He wants to know why (Acts 21:30–34). He's brought Paul to the Sanhedrin, the Jewish ruling council, to hear their point of view. It's a good idea as they're in charge of the religion and the culture of the Jews. But, they're no match for Paul.Paul begins by defending his integrity so they will listen to his witness about Jesus. The council finds his presumed righteousness offensive and has him struck. Paul notes their hypocrisy of punishing a man who has not been convicted of a crime and calls his attacker a "whitewashed wall." Bystanders point out Paul just insulted Ananias, the high priest. Paul responds with a sarcastic but well-deserved comment about Ananias' integrity (Acts 23:1–5).
When it's evident Paul is not going to be able to share about Jesus, he incites a fight between the Pharisees and Sadducees about the resurrection of the dead. The two groups fall into his trap and start fighting. The poor tribune has already learned he can't understand Paul and he can't beat him (Acts 22:1–29); now he knows he can't control him. By manipulating the Sanhedrin, Paul has shown the tribune that, like in Corinth, the disagreement is "a matter of questions about words and names and [the Jews'] own law" (Acts 18:15). The tribune realizes Paul hasn't broken the law and takes him back to the barracks to regroup.
The next day, Paul's nephew overhears a group conspire with the chief priests and elders to lure Paul into the open and kill him. When the boy tells the tribune, the army officer gives up. He sends Paul away in the middle of the night to the governor in Caesarea Maritima (Acts 23:12–35).
"Tribune" is a title for different offices. They could be tasked with administration and logistics or with leading military units. Their primary job was to protect the poor as well as the rich non-citizens from the aristocrats. In this case, he's protecting Paul from the magistrates of Jerusalem. The "barracks" refers to the Antonia Fortress built on the northwest corner of the temple mount by Herod the Great and named after Mark Antony.