Acts 23:17
Then Paul called one of the centurions unto him, and said, Bring this young man unto the chief captain: for he hath a certain thing to tell him. Then Paul called one of the centurions unto him, and said, Bring this young man unto the chief captain: for he hath a certain thing to tell him.
Paul called one of the centurions to him and asked him to bring the young man to the chief captain. The young man was Paul's sister's son, his nephew, who had a certain important thing to tell the commander. This request enabled the nephew to report and reveal the plot to kill Paul, and so preserved Paul's life from the planned attack.