As Paul argued for justification by faith, he had to answer the question of Jewish privilege. The law was given to the Jews and Christ came to the Jews as their Messiah. So what place do the Gentiles have in all of this?
16 For this reason it is by faith, that it might be in accordance with grace, in order that the promise may be certain to all the descendants, not only to those who are of the Law, but also to those who are of the faith of Abraham, who is the Father of us all,
17 (as it is written, "A Father of many nations have I made you") in the sight of Him whom he believed, even God, who gives life to the dead and calls into being that which does not exist. (Rom 4:16-17)
Paul went back to the Book of Genesis pointing out that the purpose of the calling of Abraham was to be a blessing to the nations. Further, he would become the Father of many nations. Paul argued, therefore, that the door of faith and justification was thrown completely open to the Gentiles or non-Jews. So the purpose of the calling of Abraham was to be a blessing to all the nations of the earth, and the sending of Jesus Christ was so that Jesus could become the Savior of all the humanity.
