Repetition is a typical means of emphasis in the Bible.
Luke had a primitive word processor and had no way of underlining or making bold a text for the sake of emphasis. Remember how important these events were and what a historic change they signaled. Now the Lord had made clear that, in order to become a Christian, a Gentile did not have to become as well a Jew, especially become a Jew in respect to circumcision, food laws, and the Saturday Sabbath the principal and most sacred features of Jewish culture. There is no doubt about the issue here. Cornelius was not a Jew in the way that mattered most to Jews.