There is an incentive for Paul as an Apostle to the Gentiles to continue to seek to bring some of the Jews to Christ. They represent a bridge into God's salvation for the whole nation. And Paul knows the salvation of the nation as a whole will only increase the blessings of the World and the believing Gentiles as a whole. Israel's falling away has precipitated a movement of the Gospel upon the Gentile world and brought to them salvation and riches and reconciliation... This can only mean to Paul that their return will mean a fuller expression of that salvation, greater riches and a more enriched and vigorous experience of the abundance of life we have in Jesus Christ.