According to the law; this is added to distinguish him from a proselyte, and to let them know that he had received the gospel, not from a convert out of Gentilism, (who though they admitted, yet they had a greater jealousy over, and less kindness for), but from one like unto themselves in all things.
Related Commentaries of Acts 22:12
Acts 22:12
12 And one Ananias, a devout man according to the law, having a good report of all the Jews which dwelt there,