Acts 22:29

Then straightway they departed from him, which should have
examined him
By scourging; namely, the soldiers, who under the inspection of the centurion, and by the order of the chief captain, were binding him with thongs to scourge him, and thereby extort from him his crime, which was the cause of all this disturbance; but hearing that he was a Roman, either of their own accord, or rather at the order of their officers, either the centurion or chief captain, or both, left binding him, and went their way:

and the chief captain also was afraid after he knew that he was a
Roman;
lest he should be called to an account for his conduct, and his commission should be taken from him: chiefly,

and because he had bound him;
not only had commanded him to be bound with thongs to a pillar, in order to be scourged, but he had bound him with two chains, when first seized him; and, as before observed, (See Gill on Acts 22:25); it was a heinous crime to bind a Roman.