Charles Ellicott 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)

Which should have examined him.—The verb had acquired the secondary sense (just as “putting to the question” did in medieval administration of justice) of examining by torture.

Because he had bound him.—The words seem to refer to the second act of binding (Acts 22:25) rather than the first (Acts 21:33). The chains fastened to the arms were thought of, as we see afterwards, when St. Paul’s citizenship was an acknowledged fact (Acts 26:29; Ephesians 3:1; Ephesians 4:1), as not incompatible with the respect due to a Roman citizen. The binding, as slaves were bound, with leather thongs, was quite another matter.