These twelve Jesus sent out with the following instructions: “Do not go among the Gentiles or enter any town of the Samaritans. Go rather to the lost sheep of Israel.” Matthew 10:5-6

            Jesus first mission was to go the Jews because of Old Testament prophecy and God’s promises to Abraham and David.  He came first to the Jews, but that doesn’t mean he came only to the Jews.  The Gentiles were an important part of the equation and they would only receive the Gospel if the Jews first confirmed it.  So yes, the Jews needed to believe first so the Gentiles and the whole world could believe next.