Expositor's Bible Commentary Commentary Acts 22:29

"They then that were about to examine him straightway departed from him: and the chief captain also was afraid when he knew that he was a Roman, and because he had bound him." — Acts 22:29 (ASV)

That Paul was a Roman citizen put the situation in a different light (cf. 16:37– 39). Examination under torture, while suitable for ordinary people in the empire, had to be abandoned; some other way of determining the nature of the charge had to be found. Undoubtedly the commander shuddered as he realized how close he had come to perpetrating a serious offense against a Roman citizen.