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 promised to 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. This theme is introduced at the opening of the Gospel of Luke, when Jesus, rejected in Nazareth, recalls that the prophets were rejected by Israel and accepted by Gentiles; at the end of the gospel he commands his disciples to preach his message to all nations, "beginning from Jerusalem." He repeats the command in Acts, telling them to preach "in Jerusalem, in all Judea and Samaria, and to the end of the Earth." They then proceed to do so, in the order outlined: first Jerusalem, then Judea, then Samaria, then the entire (Roman) world.