John Calvin on Acts 22:26-27

26. This man is a Roman. Some man may marvel that he was so credulous, who was appointed to be chief in examining Paul, that he doth affirm the thing, as if he knew it to be so. For if he ought to believe Paul’s words, every malefactor might, by this shift, have escaped punishment. But this was their manner of dealing, he which did say that he was a citizen of Rome, unless he could bring in some which knew him, or prove it lawfully, he was punished; for it was death for any man to pretend the freedom of the city falsely. Wherefore, the centurion referreth the matter unto the chief captain, as doubting thereof; and he (as we have said) doth straightway examine the matter more thoroughly. And though Luke doth not express by what testimonies Paul did prove himself to be a citizen of Rome, yet, undoubtedly, the chief captain knew the truth of the matter before he loosed him.