The Apostle Paul was part of that Israelite remnant that believed on Christ. To this day, there are tens of thousands of Israelite Christians. But, in Romans 11, Paul predicts that one day all of Israel will turn to Christ, not just a remnant, but, as a nation.
25For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in. 26And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob: 27For this is my covenant unto them, when I shall take away their sins. 28As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the fathers' sakes. 29For the gifts and calling of God are without repentance. 30For as ye in times past have not believed God, yet have now obtained mercy through their unbelief: 31Even so have these also now not believed, that through your mercy they also may obtain mercy.
Verse 28 is just as relevant today as it was when Paul wrote it. There has never been a fiercer enemy of Christianity than Jews. Jesus told his desciples that the world would hate them, but, it hated him before it hated them. This is especially true of Jews. They're the ones that had Him crucified and the first persecution against the Christan church was carried out by Jews, including the first martyrdom. But, verse 28 is saying that although the Jews are enemies to Christians because of the gospel of Christ, they're still beloved by God (although separated now by their unbelief) because God has still elected them (in other words, God still intends to turn them toward Him in the future).