What does Acts 23:13 mean?

Paul's life has been marked by violence ever since the murder of Stephen (Acts 7:54–60). At first, he was the perpetrator, hunting Jesus-followers everywhere from Jerusalem to Damascus (Acts 8:1–3; 9:1–2). Once he began his traveling ministry, walking through modern-day Turkey, Macedonia, and Greece to plant churches, he became the victim. In a letter Paul wrote shortly before these events in Acts, he says, "Five times I received at the hands of the Jews the forty lashes less one. Three times I was beaten with rods. Once I was stoned. Three times I was shipwrecked; a night and a day I was adrift at sea; on frequent journeys, in danger from rivers, danger from robbers, danger from my own people, danger from Gentiles, danger in the city, danger in the wilderness, danger at sea, danger from false brothers; in toil and hardship, through many a sleepless night, in hunger and thirst, often without food, in cold and exposure" (2 Corinthians 11:24–27).

Paul has returned to Jerusalem to deliver support for the church, but the violence follows him. Jews from the province of Asia in southwest modern-day Turkey saw him in the city with a Gentile they know from Ephesus. They later saw Paul in the temple and assumed he had brought Trophimus with him. In response, they incited a mob who tried to kill him (Acts 21:27–36).

The Roman guards rescued Paul by arresting him, but the tribune wanted to know what was really going on. He ordered the centurion to use the standard Roman way of extracting information: scourging. Paul barely escaped by mentioning he is a Roman citizen and they can't beat him if they haven't convicted him of a crime (Acts 22:23–29).

The tribune takes Paul to the Sanhedrin to see if they can explain. Paul's lack of tact led him to insult the high priest, after which the Pharisees and Sadducees set to fighting against each other. The tribune pulled Paul away before he was torn to pieces (Acts 23:1–10).

So, when forty Jews make a vow to kill Paul, neither he nor the tribune can be surprised. The assassins ask for the assistance of the Sanhedrin and lie in wait. Fortunately, Paul's nephew overhears their plans and tells the tribune. For the third time the tribune rescues Paul, this time by sending him to the governor in Caesarea Maritima (Acts 23:14–24).

We aren't told who Paul's attempted murderers are. They're possibly his initial accusers, the Jews from Asia (Acts 21:27). In Asia, Paul seems to only have spent significant time in Ephesus. There's no record of him having a major dispute with the Jews there, but the fallout of his ministry with the magicians and Artemis-worshipers may have made life very uncomfortable for the Jews (Acts 19:11–41).