The Gospel of Jesus Christ was sent to the Jews first. From Moses, all the way down through the prophets, in every epoch of history where God reached out to the children of Israel, the efforts God made and everything He did to reach out to them was centered on the Kingdom of God coming to their hearts. That was ultimately fulfilled in Jesus Christ. But the Jews rejected Him and thus the Gospel message. So after experiencing the full force of that rejection, Paul focused the rest of his energy, efforts, and priorities on bringing the Kingdom of God and the Hope that comes with it, to the Gentiles. It is because of this reason, our churches exist today. It is because of Paul's faith and focus that we have the hope, the life, the power, and the energy to keep this message alive and moving, transforming lives for the better, for eternity. That is the power of God in motion through Jesus Christ.