John Calvin Commentary 1 Corinthians 9:3

"My defence to them that examine me is this." — 1 Corinthians 9:3 (ASV)

My defense. Besides the main subject he is currently addressing, it also appears to have been his intention to refute, in passing, the slanders of those who loudly protested against his calling, as if he were an ordinary minister. “I am accustomed,” he says, “to present you as my shield, if anyone detracts from the honor of my Apostleship.” Therefore, it follows that the Corinthians are harmful and hostile to themselves if they do not acknowledge him as an apostle. For if their faith was a solemn testimony to Paul’s Apostleship, and his defense against slanderers, the one could not be invalidated without the other also being undermined.

Where others translate — those who interrogate me, I have rendered it as — those that examine me — for he refers to those who disputed his Apostleship. Latin writers, I confess, speak of a criminal being interrogated according to the laws, but the meaning of the Greek word ἀνακρίνειν, which Paul uses, seemed to me to be better conveyed in this way.