Apostles
Later in the Gospel narratives the twelve apostles are described as having been commissioned to preach the Gospel to "all the nations", regardless of whether Jew or Gentile. Paul emphasized the important role of the apostles in the church of God when he said that the household of God is "built upon the foundation of apostles and prophets, Christ Jesus himself being the cornerstone".
Although not one of the apostles commissioned during the life of Jesus, Paul, a Jew named Saul of Tarsus, claimed a special commission from the risen Jesus and is considered "the apostle of the Gentiles", for his missions to spread the gospel message after his conversion. In his writings, the epistles to Christian churches throughout the Levant, Paul did not restrict the term "apostle" to the Twelve, and often refers to his mentor Barnabas as an apostle. The restricted usage appears in the Revelation to John.
Acts of the Apostles
Luke–Acts is an attempt to answer a theological problem, namely how the Messiah of the Jews came to have an overwhelmingly non-Jewish church; the answer it provides, and its central theme, is that the message of Christ was sent to the Gentiles because the Jews rejected it. Luke–Acts can be also seen as a defense of (or "apology" for) the Jesus movement addressed to the Jews: the bulk of the speeches and sermons in Acts are addressed to Jewish audiences, with the Romans serving as external arbiters on disputes concerning Jewish customs and law. On the one hand, Luke portrays the Christians as a sect of the Jews, and therefore entitled to legal protection as a recognised religion; on the other, Luke seems unclear as to the future God intends for Jews and Christians, celebrating the Jewishness of Jesus and his immediate followers while also stressing how the Jews had rejected God's promised Messiah.